A three core-drawing mold structure

Abstract

The application discloses a three-time core-pulling mold structure, which comprises an upper mold plate, a cavity plate, a lower mold plate and a supporting plate, the upper mold plate is connected with a first bending pin, a second bending pin and a locking rod, the cavity plate is internally provided with an outer inclined ejector core, the inner inclined ejector core is slidably arranged in the outer inclined ejector core, a first core-pulling sliding block is movably arranged on one side of the cavity plate, a second core-pulling sliding block is movably arranged on the other side of the cavity plate, a lateral core is arranged at one end of the second core-pulling sliding block, an elastic ejector driving element is arranged between the cavity plate and the lower mold plate, a locking assembly is arranged between the cavity plate and the lower mold plate, the lower mold plate is provided with a wedge block, and the wedge block is connected with the outer inclined ejector core. The application only uses a machine opening force as a power source, sequentially uses the first bending pin, the locking rod and the second bending pin for three-time core pulling, does not need to additionally increase a driving device, the core-pulling mode is simple and easy to implement, the structure of the injection mold is simplified, the volume of the injection mold is reduced, and the production and manufacturing cost of the mold and the injection cost of products are reduced.

Description

Technical Field

[0001] This invention belongs to the field of injection mold technology, specifically relating to a three-stage core-pulling mold structure. Background Technology

[0002] Injection molds are essential process equipment for producing various industrial products. With the rapid development of the plastics industry and the widespread application of plastic products in sectors such as aviation, aerospace, electronics, machinery, shipbuilding, and automobiles, the application of injection molds is becoming increasingly extensive. An injection mold is a tool for producing plastic products, giving them a complete structure and precise dimensions. Injection molding is a processing method used for the mass production of certain complex-shaped parts. Specifically, it involves injecting molten plastic under high pressure into a mold cavity using an injection molding machine, followed by cooling and solidification to obtain the molded product. During the injection molding process, due to the special requirements of the product, the demolding direction of a certain part of the product may not be consistent with the mold opening direction of the injection molding machine, resulting in an undercut. Except in very rare cases where forced demolding is possible, in most cases, lateral parting and core pulling are required to successfully eject the product.

[0003] In some injection molds, due to the structural limitations of the injection molded product, such as Figure 6 The injection molded product shown has a mold structure with an outer inclined ejector core that disengages from the inner snap-fit, and an inner inclined ejector core interspersed with a side core. This type of mold structure often requires multiple core pullings and opening and closing the mold in a certain order. Multiple core pullings require multiple drive mechanisms, which leads to problems such as complex mold structure and core pulling steps, and large space occupation. Summary of the Invention

[0004] The purpose of this invention is to provide a three-stage core-pulling mold structure to solve the above-mentioned problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a three-stage core-pulling mold structure, comprising an upper template, a cavity plate, a lower template, and a support plate arranged sequentially; a first parting surface is provided between the upper template and the cavity plate; the upper template is connected to a first bent pin, a second bent pin, and a locking rod; an outer inclined top core is provided inside the cavity plate, and an inner inclined top core is slidably provided inside the outer inclined top core; a first core-pulling slider is movably provided on one side of the cavity plate for driving the inner inclined top core to slide along the outer inclined top core, and the first core-pulling slider is linked and cooperated with the first bent pin; a second core-pulling slider is movably provided on the other side of the cavity plate, and the second core-pulling slider is linked and cooperated with the second bent pin; one end of the second core-pulling slider is provided with a lateral core; a second parting surface is provided between the cavity plate and the lower template; an elastic top drive is provided between the cavity plate and the lower template for driving the second parting surface to open; and a locking assembly is provided between the cavity plate and the lower template, and the locking assembly is linked and cooperated with the locking rod; the lower template is provided with a wedge block, and the wedge block is connected to the outer inclined top core.

[0006] As an optional implementation of the above technical solution, the three-stage core-pulling mold structure has three core-pulling strokes during mold opening. In the first core-pulling stroke, the machine's mold opening force drives the upper mold plate, along with the first bent pin, the second bent pin, and the locking rod, to move. The first parting surface opens, the first bent pin drives the first core-pulling slider to move laterally, and the first core-pulling slider drives the inner inclined top core to slide along the outer inclined top core, causing one end of the inner inclined top core to detach from the injection molded product, completing the first core-pulling. In the second core-pulling stroke, the locking rod triggers the locking assembly to unlock the cavity plate and the lower mold plate. The elastic top drive drives the second parting surface to open, and the lower mold plate, along with the outer inclined top core, moves away from the cavity plate, causing one end of the outer inclined top core to detach from the injection molded product, completing the second core-pulling. In the third core-pulling stroke, the second bent pin drives the second core-pulling slider to move laterally, causing the lateral core at one end of the second core-pulling slider to detach from the injection molded product, completing the third core-pulling.

[0007] As an optional implementation of the above technical solution, the locking assembly includes a locking block and a locking buckle that cooperate with each other. The locking block is disposed on the cavity plate, and the locking buckle is disposed on the lower template. The locking buckle is equipped with an elastic unlocking element and is disposed on the movement path of the locking rod. When the locking rod separates from the locking buckle, the locking buckle separates from the locking block under the action of the elastic unlocking element, thereby unlocking the cavity plate and the lower template.

[0008] As an optional implementation of the above technical solution, the locking block is provided with a first step, and the latch is provided with a second step that engages with the first step.

[0009] As an optional implementation of the above technical solution, the elastic unlocking component includes an unlocking spring, which is used to apply a lateral force to the latch to spring it open, so as to separate the latch from the lock block.

[0010] As an optional implementation of the above technical solution, the end of the locking rod is provided with an inclined guide surface.

[0011] As an optional implementation of the above technical solution, one end of the first core-pulling slider is provided with a slanted plug, the outer slanted top core is provided with a strip hole, the inner slanted top core is provided with a slanted insertion hole, and one end of the slanted plug passes through the strip hole and extends into the slanted insertion hole.

[0012] As an optional embodiment of the above technical solution, the elastic top drive component includes a top drive spring, the cavity plate is provided with an upper mounting groove, the lower template is provided with a lower mounting groove, and the top drive spring is disposed between the upper mounting groove and the lower mounting groove.

[0013] As an optional implementation of the above technical solution, the inclined wedge block is provided with an inclined sliding groove, and one end of the outer inclined top core is provided with a sliding part adapted to the inclined sliding groove.

[0014] As an optional implementation of the above technical solution, the first core-pulling slider has a first oblique guide hole that is adapted to the first bent pin.

[0015] As an optional implementation of the above technical solution, the second core-pulling slider has a second oblique guide hole that is adapted to the second bent pin.

[0016] The beneficial effects of this invention are as follows:

[0017] This invention provides a three-stage core-pulling mold structure that uses only the machine's mold-opening force as a power source. It utilizes a first bent pin, a locking rod, and a second bent pin to perform three sequential core-pulling operations without the need for additional drive equipment. This core-pulling method is simple and easy to implement, which simplifies the structure of the injection mold, reduces the size of the injection mold, lowers the mold production cost and product injection molding cost, and effectively ensures the molding quality of the injection molded product. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a three-stage core-pulling mold structure according to one embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram illustrating the engagement of the outer inclined core, the inner inclined core, and the lateral core in one embodiment of the present invention.

[0020] Figure 3 This is an exploded schematic diagram of the outer inclined core, the inner inclined core, and the lateral core in one embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of the locking rod and locking assembly in one embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the core-pulling process of a three-stage core-pulling mold structure in one embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the structure of the injection-molded product in this invention.

[0024] In the diagram: 1-Upper template; 2-Cavity plate; 3-Lower template; 4-Support plate; 5-First parting surface; 6-First bent pin; 7-Second bent pin; 8-Locking rod; 9-Outer inclined top core; 10-Inner inclined top core; 11-First core-pulling slider; 12-Second core-pulling slider; 13-Side core; 14-Second parting surface; 15-Inclined wedge block; 16-Locking block; 17-Lock; 18-Unlocking spring; 19-Angled plug; 20-Strip hole; 21-Angled insertion hole; 22-Top drive spring; 23-Injection molded product; 24-Inner buckle. Detailed Implementation

[0025] like Figures 1-5 As shown, this embodiment provides a three-stage core-pulling mold structure for producing materials such as... Figure 6 The injection molded product 23 shown has a mold structure including an upper mold plate 1, a cavity plate 2, a lower mold plate 3, and a support plate 4, which are arranged sequentially from top to bottom. A first parting surface 5 is provided between the upper mold plate 1 and the cavity plate 2. The upper mold plate 1 is connected to a first bent pin 6, a second bent pin 7, and a locking rod 8. The first bent pin 6 and the second bent pin 7 are both bent, while the locking rod 8 is straight. When the upper mold plate 1 moves, it can move the first bent pin 6, the second bent pin 7, and the locking rod 8 together.

[0026] The cavity plate 2 has an outer inclined top core 9 inside, and an inner inclined top core 10 is slidably disposed inside the outer inclined top core 9. Both ends of the outer inclined top core 9 are open, and the top of the outer inclined top core 9 has a first forming part. The inner inclined top core 10 is slidably disposed inside the outer inclined top core 9, and the top of the inner inclined top core 10 extends to the outside of the outer inclined top core 9 and has a second forming part. A first core-pulling slider 11 is movably disposed on one side of the cavity plate 2 to drive the inner inclined top core 10 to slide along the outer inclined top core 9. The first core-pulling slider 11 is engaged with a first bent pin 6. Preferably, the first core-pulling slider 11 has a first oblique guide hole adapted to the first bent pin 6. When the straight part of the first bent pin 6 passes through the first oblique guide hole, the first core-pulling slider 11 remains stationary; when the bent part of the first bent pin 6 passes through the first oblique guide hole, the first core-pulling slider 11 moves to the left. When the first bent pin 6 moves upward to the appropriate position along with the upper template 1, the first bent pin 6 drives the first core-pulling slider 11 to slide to the left, and the first core-pulling slider 11 drives the inner inclined top core 10 to slide downward at an angle, so that the inner inclined top core 10 disengages from the inner buckle 24 of the injection molded product 23.

[0027] A second core-pulling slider 12 is movably provided on the other side of the cavity plate 2, and the second core-pulling slider 12 is linked and engaged with the second bent pin 7. Preferably, the second core-pulling slider 12 has a second oblique guide hole adapted to the second bent pin 7. When the straight part of the second bent pin 7 passes through the second oblique guide hole, the second core-pulling slider 12 remains stationary; when the curved part of the second bent pin 7 passes through the second oblique guide hole, the second core-pulling slider 12 moves to the right. One end of the second core-pulling slider 12 is provided with a lateral core 13, and the end of the lateral core 13 is provided with a third forming part. The second core-pulling slider 12 and the lateral core 13 adopt an integral molding structure. When the second bent pin 7 moves upward with the upper mold plate 1 to a suitable position, the second bent pin 7 drives the second core-pulling slider 12 to slide to the right, so that the lateral core 13 is disengaged from the injection molded product.

[0028] like Figure 1As shown, a second parting surface 14 is provided between the cavity plate 2 and the lower template 3. An elastic top drive is provided between the cavity plate 2 and the lower template 3 to drive the second parting surface 14 to open, and a locking assembly is provided between the cavity plate 2 and the lower template 3. The locking assembly is linked and cooperates with the locking rod 8. The lower template 3 is provided with a wedge block 15, which is connected to the outer inclined top core 9. When the locking rod 8 moves upward with the upper template 1 to a suitable position, the locking assembly unlocks the cavity plate 2 and the lower template 3. Under the action of the elastic top drive, the second parting surface 14 opens, and the lower template 3, the wedge block 15, and the outer inclined top core 9 gradually move away from the cavity plate 2 and the injection molded product 23, causing the outer inclined top core 9 to detach from the injection molded product 23.

[0029] The three-stage core-pulling mold structure of the present invention has three core-pulling strokes during mold opening, namely the first core-pulling stroke, the second core-pulling stroke, and the third core-pulling stroke. Because the injection molded product 23 has an inner snap-fit ​​24, the inner inclined top core 10 needs to be pulled out to disengage the inner snap-fit ​​24 first. The inner inclined top core 10 is driven by the first core-pulling slider 11, so the first step is to pull out the first core-pulling slider 11. During the first core-pulling stroke, the upper mold plate 1, along with the first bent pin 6, the second bent pin 7, and the locking rod 8, moves upward using the mold opening force of the machine. The first parting surface 5 opens, and the first bent pin 6 drives the first core-pulling slider 11 to move horizontally to the left. The first core-pulling slider 11 drives the inner inclined top core 10 to slide downward along the outer inclined top core 9, causing the top of the inner inclined top core 10 to detach from the injection molded product, completing the first core-pulling. During the second core-pulling stroke, the locking rod 8 triggers the locking assembly to unlock the cavity plate 2 and the lower mold plate 3. The elastic top drive drives the second parting surface 14 to open, and the lower mold plate 3 and the cavity plate 2 move away from each other, causing the top of the outer inclined top core 9 to detach from the injection molded product, completing the second core-pulling. During the third core-pulling stroke, the second bent pin 7 drives the second core-pulling slider 12 to move horizontally to the right, causing the side core 13 at one end of the second core-pulling slider 12 to detach from the injection molded product, completing the third core-pulling.

[0030] This invention uses only the mold opening force of the machine as the power source, and uses the first bent pin 6, the locking rod 8 and the second bent pin 7 to perform three sequential core pullings. No additional drive equipment is required. This core pulling method is simple and easy to implement. It simplifies the structure of the injection mold, reduces the volume of the injection mold, reduces the mold production cost and the product injection molding cost, and can effectively ensure the molding quality of the injection molded product.

[0031] like Figure 4As shown, in this embodiment, the locking assembly includes a locking block 16 and a latch 17 that cooperate with each other. The locking block 16 is disposed on the cavity plate 2, and the latch 17 is disposed on the lower template 3. The latch 17 is equipped with an elastic unlocking element and is disposed on the movement path of the locking rod 8. When the locking rod 8 separates from the latch 17, the latch 17 separates from the locking block 16 under the action of the elastic unlocking element, thereby unlocking the cavity plate 2 and the lower template 3. Specifically, the elastic unlocking element includes an unlocking spring 18, which applies a lateral force to the latch 17 to spring it open, thereby separating the latch 17 from the locking block 16. Preferably, the locking block 16 has a first step, and the latch 17 has a second step that engages with the first step. Further, the end of the locking rod 8 has a beveled guide surface.

[0032] The wedge block 15 is provided with an inclined groove, and one end of the outer inclined top core 9 is provided with a sliding part adapted to the inclined groove. When the lower mold plate 3 and the wedge block 15 move downward together, the sliding part slides along the inclined groove, while simultaneously sliding the outer inclined top core 9 downward at an angle, so that the outer inclined top core 9 gradually separates from the injection molded product. During the first core pulling stroke, the locking rod 8 holds the locking buckle 17, the unlocking spring 18 is compressed, the first step and the second step are interlocked, and the locking buckle 17 and the locking block 16 lock the cavity plate 2 and the lower mold plate 3. During the second core pulling stroke, the locking rod 8 separates from the locking buckle 17. After the locking buckle 17 loses the lateral pressure of the locking rod 8, under the action of the unlocking spring 18, the locking buckle 17 slides laterally, and the locking buckle 17 and the locking block 16 separate from each other, realizing the unlocking function of the cavity plate 2 and the lower mold plate 3. At this point, under the action of the elastic top drive, the cavity plate 2 and the lower mold plate 3 separate from each other, the second parting surface 14 opens, and the lower mold plate 3, carrying the inclined wedge block 15 and the outer inclined top core 9, gradually moves away from the cavity plate 2 and the injection molded product, causing the top of the outer inclined top core 9 to detach from the injection molded product, completing the second core pulling. The mold structure of this invention is reasonably designed, compact, stable in operation, safe and reliable, and convenient to use.

[0033] like Figure 3 As shown, in one specific embodiment, one end of the first pull-out slider 11 is provided with a beveled plug 19. The first pull-out slider 11 and the beveled plug 19 are integrally formed. The outer beveled top core 9 has a strip-shaped hole 20, and the inner beveled top core 10 has a beveled insertion hole 21. One end of the beveled plug 19 passes through the strip-shaped hole 20 and extends into the beveled insertion hole 21. Figure 2 As shown, when the first core-pulling slider 11 moves to the left, the angled plug 19 gradually disengages from the angled insertion hole 21. At the same time, the angled plug 19 drives the inner angled top core 10 to slide obliquely downward along the outer angled top core 9, causing the top of the inner angled top core 10 to disengage from the injection molded product.

[0034] like Figure 1As shown, in this embodiment, the elastic top drive component includes a top drive spring 22, the cavity plate 2 is provided with an upper mounting groove, the lower template 3 is provided with a lower mounting groove, and the top drive spring 22 is disposed between the upper mounting groove and the lower mounting groove.

[0035] The three-stage core-pulling mold structure of this invention requires no additional driving force, relying solely on the driving force provided by the machine's mold opening mechanism. This single driving force mechanically completes the three-stage sequential core-pulling and demolding, offering flexible application and a wide range of uses. Specifically, the three-stage sequential core-pulling is as follows: For the first core-pulling, the first parting surface 5 opens, while the second parting surface 14 remains stationary due to the locking assembly being closed. The first bent pin 6 drives the first core-pulling slider 11 to slide to the left. Since the second bent pin 7 is in a delayed state, the second core-pulling slider 12 remains stationary. The first core-pulling slider 11 drives the inner inclined top core 10 to slide along the outer inclined top core 9, causing one end of the inner inclined top core 10 to detach from the injection molded product, completing the first core-pulling. For the second core-pulling, the locking rod 8 disengages from the locking buckle 17, the second parting surface 14 opens, and since the second bent pin 7 is in a delayed state, the second core-pulling slider 12 remains stationary. The lower mold plate 3 and the support plate 4 move downwards together, and the outer inclined top core 9 slides downwards at an angle, causing the top of the outer inclined top core 9 to detach from the injection molded product, completing the second core-pulling. In the third core pulling, the second bent pin 7 drives the second core pulling slider 12 to slide to the right until the mold is fully opened, and the side core 13 at one end of the second core pulling slider 12 is separated from the injection molded product, completing the third core pulling.

[0036] like Figure 5 As shown, the combined motion of the three-stage core-pulling mold structure in this invention is as follows:

[0037] 1. Initial state: The state of the product after mold closing and injection molding is complete;

[0038] 2. Inner inclined core 10 disengages from inner latch 24 (first core pulling): Driven by the mold opening force of the machine, the first parting surface 5 opens, and the second parting surface 14 remains stationary because the locking assembly is in the closed state. Therefore, the outer inclined core 9 remains stationary. The first bent pin 6 drives the first core pulling slider 11 to slide to the left, and the second bent pin 7 is in a delayed state, so the second core pulling slider 12 remains stationary. At this time, only the first core pulling slider 11 moves, causing the inner inclined core 10 to move diagonally downwards, disengaging from the inner latch 24, completing the first core pulling.

[0039] 3. Outer inclined core 9 disengages (second core pulling): The machine continues to open the mold, the locking rod 8 disengages from the locking buckle 17, the top drive spring 22 drives the second parting surface 14 to open, the inclined wedge block 15 moves downward, the inclined wedge block 15 drives the outer inclined core 9 to move obliquely downward, so that the top of the outer inclined core 9 disengages from the inserted part of the injection molded product, completing the second core pulling. Since the second bent pin 7 is in a delayed state, the second core pulling slider 12 remains stationary.

[0040] 4. Side core 13 disengagement (third core pulling): The machine continues to open the mold, the second bending pin 7 delay section ends, the second bending pin 7 drives the second core pulling slider 12 to slide to the left, so that the side core 13 disengages from the injection molded product, and the third core pulling is completed.

[0041] 5. After completing three core-pulling actions, the product can be ejected.

[0042] The mold structure of the present invention is reasonably and compactly designed, which can reduce the mold size, reduce the mold manufacturing cost, and improve economic efficiency.

[0043] In the description of this invention, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. They can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical or electrical connections; they can refer to direct connections or indirect connections 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 will understand the specific meaning of these terms in this invention. Furthermore, the specific features and structures described in the embodiments are included in at least one implementation method. Those skilled in the art can combine features from different implementation methods without contradiction. The scope of protection of this invention is not limited to the specific implementation methods described above. Based on the basic technical concept of this invention, implementation methods that can be conceived by those skilled in the art without creative effort are all within the scope of protection of this invention.

Claims

1. A three-part core mold structure comprising, in order, an upper mold plate (1), a cavity plate (2), a lower mold plate (3), and a support plate (4), a first parting surface (5) being provided between the upper mold plate (1) and the cavity plate (2), characterized in that, The upper die plate (1) is connected with the first bending pin (6), the second bending pin (7) and the locking rod (8); the cavity plate (2) is internally provided with an outer inclined core pin (9), the inner inclined core pin (10) is slidably arranged in the inner portion of the outer inclined core pin (9), the first core pulling slider (11) for driving the inner inclined core pin (10) to slide along the outer inclined core pin (9) is movably arranged on one side of the cavity plate (2), the first core pulling slider (11) is connected with the first bending pin (6); the second core pulling slider (12) is movably arranged on the other side of the cavity plate (2), the second core pulling slider (12) is connected with the second bending pin (7), the lateral core pin (13) is arranged at one end of the second core pulling slider (12); the second parting surface (14) is arranged between the cavity plate (2) and the lower die plate (3), the elastic top driving element for driving the second parting surface (14) to open is arranged between the cavity plate (2) and the lower die plate (3), the locking assembly is arranged between the cavity plate (2) and the lower die plate (3), the locking assembly is connected with the locking rod (8); the inclined wedge block (15) is arranged on the lower die plate (3), the inclined wedge block (15) is connected with the outer inclined core pin (9); The three-stage core pulling mold structure has three-stage core pulling strokes when the mold is opened, in the first-stage core pulling stroke, the upper die plate (1) is driven to move with the first bending pin (6), the second bending pin (7) and the locking rod (8) by the machine opening force, the first parting surface (5) is opened, the first bending pin (6) drives the first core pulling slider (11) to laterally translate, the first core pulling slider (11) drives the inner inclined core pin (10) to slide along the outer inclined core pin (9), one end of the inner inclined core pin (10) is separated from the injection molding product, and the first-stage core pulling is completed; in the second-stage core pulling stroke, the locking rod (8) triggers the locking assembly to unlock the cavity plate (2) and the lower die plate (3), the elastic top driving element drives the second parting surface (14) to open, the lower die plate (3) with the outer inclined core pin (9) is away from the cavity plate (2), one end of the outer inclined core pin (9) is separated from the injection molding product, and the second-stage core pulling is completed; in the third-stage core pulling stroke, the second bending pin (7) drives the second core pulling slider (12) to laterally translate, the lateral core pin (13) at one end of the second core pulling slider (12) is separated from the injection molding product, and the third-stage core pulling is completed.

2. The three- draw core structure of claim 1, wherein, The locking assembly comprises the locking block (16) and the locking buckle (17) which are matched with each other, the locking block (16) is arranged on the cavity plate (2), the locking buckle (17) is arranged on the lower die plate (3), the locking buckle (17) is provided with the elastic unlocking element, the locking buckle (17) is arranged on the movement path of the locking rod (8), after the locking rod (8) is separated from the locking buckle (17), the locking buckle (17) is separated from the locking block (16) under the action of the elastic unlocking element, and the cavity plate (2) and the lower die plate (3) are unlocked.

3. The three- draw core structure of claim 2, wherein, The locking block (16) is provided with the first step, and the locking buckle (17) is provided with the second step which is matched with the first step.

4. The three-part core-drawing mold structure according to claim 2, wherein The elastic unlocking piece comprises an unlocking spring (18) for applying a transverse force to the lock catch (17) to pop the lock catch (17) apart from the lock block (16).

5. The three-part core-drawing mold structure according to claim 4, wherein The end of the lock rod (8) is provided with an inclined guide surface.

6. The three- draw core structure of claim 1 wherein, One end of the first core-pulling slider (11) is provided with an inclined plug (19), the outer inclined core (9) is provided with a strip-shaped hole (20), the inner inclined core (10) is provided with an inclined plug hole (21), and one end of the inclined plug (19) extends into the inclined plug hole (21) after passing through the strip-shaped hole (20).

7. The three- draw core structure of claim 1 wherein, The elastic top driving piece comprises a top driving spring (22), the cavity plate (2) is provided with an upper mounting groove, the lower die plate (3) is provided with a lower mounting groove, and the top driving spring (22) is arranged between the upper mounting groove and the lower mounting groove.

8. The three- draw core structure of claim 1 wherein, The inclined wedge block (15) is provided with an inclined sliding groove, and one end of the outer inclined core (9) is provided with a sliding part matched with the inclined sliding groove.

9. The three- draw core structure of claim 1 wherein, The first core-pulling slider (11) is provided with a first inclined guide hole matched with the first bent pin (6), and the second core-pulling slider (12) is provided with a second inclined guide hole matched with the second bent pin (7).

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