Core pulling structure of injection mold

Abstract

The invention provides a core pulling structure of an injection mold, and belongs to the technical field of injection molds. The core-pulling structure solves the problem that an existing core-pulling structure of an injection mold is low in structural stability and forming quality. The core pulling structure of the injection mold comprises a core slidably arranged in a movable mold in a penetrating mode, a guide shell is fixed to the movable mold, an insertion block, a push block and a transmission block are arranged in the guide shell, one end of the insertion block extends out of the guide shell, a fixed mold can inwards push the insertion block during mold closing, the outer end of the push block faces the core, and the transmission block is located between the inner end of the insertion block and the inner end of the push block. When the insertion block slides inwards and pushes the transmission block, the transmission block can push the push block outwards, an elastic piece is arranged between the core and the movable mold, one end of the core is pressed against the outer end of the push block under the action of the elastic piece, and the inner end of the push block is pressed against the transmission block. The core-pulling structure of the injection mold can improve the structural stability, so that the forming quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molds and relates to a core pulling structure of an injection mold. Background Art

[0002] Injection molds use injection molding technology to produce products. At a certain temperature, the completely molten plastic material is stirred by a screw, injected into the mold cavity with high pressure, and then cooled and solidified to obtain a molded product. Injection molds are suitable for mass production of parts with complex shapes. The shapes can be from simple to complex, and the sizes can be from large to small. When there are holes in the product, a core pulling structure is often required, especially when the product has undercuts. In addition, due to the limitations of the product appearance quality, only tunnel hole core pulling can be used.

[0003] For example, the patent document (application number: 201320668759.8) discloses a spring slider side core pulling mechanism for the cavity side of an injection mold, comprising an upper plate and a lower plate, a cavity is arranged under the upper plate, a through hole is opened in the lower plate, a plastic part is arranged between the core and the cavity, a hole is opened in the side wall of the plastic part, an inclined wedge is installed in the upper plate, a slider groove is opened on one side of the cavity, a side pull-out slider is arranged in the slider groove, a slider baffle is arranged on the outer side of the side pull-out slider, a return spring is arranged on the side pull-out slider located on one side of the slider baffle, the inner side of the inclined wedge has a straight surface and an inclined surface, a through hole is opened on the slider baffle, one end of the side pull-out slider passes through the through hole outward and contacts with the straight surface or the inclined surface of the inclined wedge, and the other end cooperates with the hole in the plastic part.

[0004] The side pull-out slider is columnar, and the outer end of the side pull-out slider rests on the inclined surface of the inclined wedge in the mold opening state. When the mold is closed, the lower reset plate moves upward, and the outer end of the side pull-out slider slides along the inclined surface to the straight surface, which is equivalent to the inclined wedge pushing the outer end of the side pull-out slider through the inclined surface, so that the side pull-out slider compresses the reset spring to slide inward and insert into the cavity. Since the inner end of the side pull-out slider is inserted into the cavity, which is equivalent to a cavity surface, the position accuracy of the inner end of the side pull-out slider directly determines the accuracy of the hole position on the product. However, the outer end of the side pull-out slider is pushed by the inclined surface of the inclined wedge. The inclined surface presses on the side pull-out slider, which will generate a component force along the axial direction of the side pull-out slider and a component force perpendicular to the axial direction of the side pull-out slider. The former component force pushes the side pull-out slider to slide, but the latter component force causes the side pull-out slider to be pressed against the through hole wall of the slider baffle. After long-term use, it will cause eccentric wear of the through hole of the slider baffle and the outer end of the side pull-out slider, and then cause the outer end of the side pull-out slider to be offset and affect the position accuracy of the inner end. Therefore, the overall stability is low, affecting the molding quality of the product. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems in the prior art and to propose a core-pulling structure for an injection mold, which can improve the structural stability and thus improve the molding quality.

[0006] The object of the present invention can be achieved through the following technical solutions: a core-pulling structure of an injection mold, the injection mold includes a movable mold and a fixed mold, the core-pulling structure includes a core that is columnar and slides in the movable mold in the transverse direction, characterized in that a guide shell is fixed on the movable mold, and an insert block, a push block and a transmission block are arranged in the guide shell. The insert block is slidably arranged along the mold closing direction of the movable mold, one end of the insert block extends out of the guide shell, and the fixed mold can push the insert block inward during mold closing, the push block is slidably arranged along the sliding direction of the core, and the outer end of the push block faces the core, the transmission block is located between the inner end of the insert block and the inner end of the push block, and when the insert block slides inward and pushes the transmission block, the transmission block can push the push block outward, an elastic member is arranged between the core and the movable mold, and under the action of the elastic member, one end of the core is pressed on the outer end of the push block, and the inner end of the push block is pressed on the transmission block.

[0007] Injection molds usually open and close vertically, that is, the movable mold moves vertically, so the core of the present application is arranged in the movable mold along the horizontal direction. However, if the injection mold opens and closes horizontally, that is, the movable mold moves horizontally, then the core of the present application is arranged in the movable mold along the vertical direction, that is, the moving direction of the core is perpendicular to the closing direction of the movable mold. During injection molding, the movable mold moves toward the fixed mold and closes the mold, the fixed mold pushes the plug block inward, the plug block moves inward and pushes the transmission block, the transmission block pushes the push block outward, the push block pushes the core, and the inner end of the core is inserted into the cavity. When the mold needs to be opened after the product is formed, the movable mold moves away from the fixed mold and releases the plug block. The core pushes the push block back under the action of the elastic member, the push block pushes the transmission block back, and the transmission block pushes the plug block back to move outward to realize core pulling. The core is inserted into the cavity using the closing force of the movable mold, and is pulled out of the cavity using the elastic force of the elastic member, without the need for additional drive members to perform core pulling. Especially when the closing direction of the movable mold is different from the core pulling direction of the core, the present application provides an insert block that can slide along the closing direction of the movable mold and a push block that can slide along the core pulling and inserting direction, and uses a transmission block to convert the sliding of the insert block along the closing direction of the movable mold into the sliding of the push block along the core pulling and inserting direction. Therefore, when the mold is closed, the core is only subjected to the thrust along the sliding direction of the core and is not subjected to other inclined force components, thereby avoiding eccentric wear between the core and the movable mold, which can not only ensure the smooth sliding of the core, but also reduce the wear between the core and the movable mold, thereby ensuring the structural stability. The core without eccentric wear has higher position accuracy, which makes the inner end more accurately inserted into the cavity, thereby ensuring the molding quality of the product.

[0008] In the core-pulling structure of the injection mold, the guide shell has a plug hole arranged along the direction of the movable mold, and the opening of the plug hole faces the side where the fixed mold is located, and the plug block is slidably inserted in the plug hole. The guide shell also has a guide hole arranged along the sliding direction of the core, the opening of the guide hole faces the core, and the inner end of the guide hole is connected to the plug hole, and the push block is slidably inserted in the guide hole. The plug hole guides the plug block so that the plug block can only move along the direction of the movable mold, and the guide hole guides the push block so that the push block can only slide along the sliding direction of the core, thereby ensuring the thrust direction of the core and avoiding eccentric wear of the core to affect stability and product quality.

[0009] In the core-pulling structure of the injection mold, a sliding hole is provided in the movable mold, the inner end of the sliding hole penetrates the cavity of the movable mold, and the outer end is coaxial with and opposite to the guide hole. The core slides through the sliding hole, and the axial direction of the core is perpendicular to the mold closing direction of the movable mold. The sliding hole guides the core to ensure its position accuracy. The sliding hole is coaxial with the guide hole, so that the core and the push block are coaxially arranged, and the two are only in abutment relationship. The push block can only transmit the thrust along the sliding direction of the core to the core, and will not generate forces in other directions on the core, so as to avoid eccentric wear of the core and affect stability and product quality.

[0010] In the core pulling structure of the injection mold, the inner bottom surface of the jack is a guide slope, and the end of the guide slope close to the guide hole is inclined in the direction away from the jack opening, the transmission block abuts on the guide slope, and the thickness of the transmission block along the sliding direction of the push block is less than the width of the jack along the sliding direction of the push block. The thickness of the transmission block and the width of the jack are set so that there is space in the mounting shell for the transmission block to move along the sliding direction of the core, and the guide shell adopts a guide slope to cooperate with the transmission block, that is, the transmission block always abuts on the guide slope, and when the plug pushes the transmission block inward, the transmission block slides along the guide slope, and the guide slope converts the inward sliding of the transmission block into sliding in the direction of the push block, and the guide slope plays the role of a reference surface. Compared with the transmission structure with assembly clearance such as a gear rack, the travel and position accuracy of the transmission block are higher, thereby ensuring the position accuracy of the core to improve the molding quality of the product.

[0011] In the core-pulling structure of the injection mold, the longitudinal section of the transmission block is trapezoidal, and the inclined surface at one end of the transmission block is against the guiding inclined surface, and the inclined surface at the other end is against the inner end of the plug block. The transmission block also has a push plane facing the guide hole and perpendicular to the center line of the guide hole, and the inner end face of the push block is fitted against the push plane. The transmission block fits the guiding inclined surface through the inclined surface at one end, giving full play to the reference surface function of the guiding inclined surface, so that the position accuracy is higher, the push plane is perpendicular to the center line of the guide hole, that is, perpendicular to the sliding direction of the push, and then generates a thrust along the sliding direction of the push block. Further, the transmission block is converted into movement toward the core by moving inward, so the push plane will generate a sliding friction perpendicular to the sliding direction of the core. This is also the purpose of setting an independent push block in this application, so that the sliding friction acts on the push block instead of the core. The push block can be constrained and guided by the guide hole to offset the sliding friction, so that the core is only subjected to the thrust along its sliding direction, improving stability.

[0012] In the core-pulling structure of the injection mold, the push block is cylindrical, and the inner peripheral wall of the push block has a convex shoulder in the circumferential direction, the guide hole is a round hole, and the inner end opening of the guide hole has a flared opening, the area of ​​the push plane is larger than the area of ​​the flared opening, and the convex shoulder is embedded in the flared opening when the push plane pushes the push block outward and abuts against the wall of the jack. The wall of the jack limits the transmission block, so that when the transmission block abuts against the wall of the jack, the convex shoulder of the push block is embedded in the flared opening, and the core is inserted into the cavity in place, thereby improving the molding quality of the product.

[0013] In the core-pulling structure of the injection mold, the plug block is in a rectangular block shape, and the inner end face of the plug block is a push-up bevel, the end of the push-up bevel close to the guide hole is inclined toward the direction of the jack hole, and the push-up bevel is in contact with the bevel of the adjacent end of the transmission block. The rectangular block-shaped plug block cooperates with the jack, and has better stability. The inner end of the plug block is in contact with the bevel of the transmission block through the push-up bevel, so that there is no matching gap between the plug block and the transmission block, and between the transmission block and the push block, so that the transmission accuracy is higher, and the stability between the plug block, the transmission block and the push block is higher.

[0014] In the core-pulling structure of the injection mold, a limit pin is fixed on the wall of the jack hole, and a strip-shaped limit groove is provided on the side of the plug block along the sliding direction, and the limit pin is inserted into the limit groove. When the movable mold and the fixed mold are opened, the plug block is released, and the limit pin can prevent the plug block from falling out of the guide shell, thereby ensuring the stability of the structure.

[0015] In the core-pulling structure of the injection mold, a pressure block is fixed on the side wall of the fixed mold, and the pressure block is opposite to the outer end of the plug-in block. When the movable mold and the fixed mold are closed, the pressure block can push the plug-in block inward. When the movable mold and the fixed mold are closed, the fixed mold presses the plug-in block through the pressure block, and the structure is more stable.

[0016] In the core-pulling structure of the above-mentioned injection mold, a mounting groove is provided on the side of the pressure block facing the plug block, and a screw hole is provided on the side of the pressure block facing away from the plug block. The inner end of the screw hole passes through the bottom surface of the mounting groove, and an adjusting bolt is threaded in the screw hole. A disc spring and two pads are provided in the mounting groove. The disc spring is located between the two pads, and when the movable mold and the fixed mold are closed, one pad is pressed against the inner end of the adjusting bolt, and the other pad is pressed against the outer end of the plug block. The position of the movable mold and the fixed mold when they are closed is fixed, and the position accuracy is very high. However, the pressure block and the guide shell are separately installed and fixed on the fixed mold and the movable mold. The position accuracy between the pressure block and the installation shell needs to meet the position accuracy between the fixed mold and the movable mold. If there is a deviation in the relative position between the pressure block and the guide shell, then when the movable mold and the fixed mold are closed, the pressure block may not be pressed in place or over-pressed, resulting in excessive wear of the plug block and the transmission block. For this reason, a pad and a disc spring are set in the pressure block. When closing the mold, the plug block acts on the pad, and the pad presses the disc spring to deform. Then, under the elastic force of the disc spring, the pad pushes the plug block to avoid affecting the structural stability due to assembly deviation. At the same time, an adjustment bolt is also provided to adjust the preload force when the pad pushes the plug block to suit different molds.

[0017] Compared with the prior art, the core-pulling structure of the injection mold has the following advantages:

[0018] 1. Since the transmission block of the present application can move to the side where the core is located under the push of the insertion block, thereby pushing the push block along the sliding direction of the core, the transmission block and the push block both generate thrust along the sliding direction of the core, that is, the joint action of the transmission block and the push block is utilized, so that the core is only subjected to the thrust along the sliding direction of the core, eliminating other inclined force components, thereby avoiding eccentric wear between the core and the movable mold, which can not only ensure the smooth sliding of the core, but also reduce the wear between the movable core and the movable mold, thereby ensuring the structural stability. The core without eccentric wear has higher position accuracy, making the inner end more accurately inserted into the cavity, thereby ensuring the molding quality of the product.

[0019] 2. Since the guide shell adopts a guide slope to cooperate with the transmission block, the transmission block always rests on the guide slope, and when the insert block pushes the transmission block inward, the transmission block slides along the guide slope. The guide slope acts as a reference surface, and the travel and position accuracy of the transmission block are higher, thereby ensuring the position accuracy of the core to improve the product molding quality.

[0020] 3. Since the present application sets up an independent push block, the sliding friction force generated by the transmission block acts on the push block instead of the core. The push block can be constrained and guided by the guide hole to offset the sliding friction force, so that the core is only subjected to the thrust along its sliding direction, thereby improving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the injection mold when it is in the mold closing state.

[0022] Figure 2 It is a structural cross-sectional view of the injection mold when it is in the mold closing state.

[0023] Figure 3 yes Figure 2 A magnified view of the structure at center.

[0024] Figure 4 It is a schematic diagram of the three-dimensional structure of the movable mold when the injection mold is in the open mold state.

[0025] Figure 5 It is a partial structural cross-sectional view of the core pulling structure in the second embodiment.

[0026] In the figure, 1, movable mold; 11, sliding hole; 111, step surface; 12, cavity; 2, fixed mold; 3, core; 4, guide shell; 41, shell; 42, cover plate; 43, plug hole; 44, guide hole; 441, flaring; 45, guide inclined surface; 46, limit pin; 47, pressure relief hole; 5, plug block; 51, push inclined surface; 52, limit groove; 6, push block; 61, boss; 7, transmission block; 71, push plane; 8, elastic member; 9, pressure block; 91, mounting groove; 92, screw hole; 93, adjusting bolt; 94, disc spring; 95, gasket. DETAILED DESCRIPTION

[0027] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0028] Embodiment 1:

[0029] like Figure 1 , Figure 2 , Figure 3As shown, a core-pulling structure of an injection mold, the injection mold includes a movable mold 1 and a fixed mold 2, and a cavity 12 is formed when the fixed mold 2 and the fixed mold 2 are closed. The core-pulling structure includes a core 3, which is columnar, and a sliding hole 11 is opened in the movable mold 1. The length direction of the sliding hole 11 is perpendicular to the closing direction of the movable mold 1, and the inner end of the sliding hole 11 passes through the cavity 12. The outer end of the sliding hole 11 has a step surface 111. The core 3 is slidably arranged in the sliding hole 11, that is, the sliding direction of the core 3 is perpendicular to the closing direction of the movable mold 1. An elastic member 8 is sleeved on the core 3, and the elastic member 8 is a spring. One end of the spring abuts on the step surface 111 of the sliding hole 11, and the other end abuts on the core 3. When the core 3 compresses the spring and slides inward, it can be inserted into the cavity 12. A guide shell 4 is fixed on the movable mold 1, and an insert block 5, a push block 6 and a transmission block 7 are arranged in the guide shell 4. The insert block 5 is slidably arranged along the mold closing direction of the movable mold 1, and one end of the insert block 5 extends out of the guide shell 4. A pressure block 9 is fixed on the side wall of the fixed mold 2, and the pressure block 9 is opposite to the outer end of the insert block 5. When the movable mold 1 and the fixed mold 2 are molded, the pressure block 9 can push the insert block 5 inwardly. The push block 6 is slidably arranged along the sliding direction of the core 3, and the outer end of the push block 6 faces the core 3. The transmission block 7 is located between the inner end of the insert block 5 and the inner end of the push block 6, and when the insert block 5 slides inwardly and pushes the transmission block 7, the transmission block 7 can push the push block 6 outwardly. Under the action of the spring, one end of the core 3 presses on the outer end of the push block 6, and the inner end of the push block 6 presses on the transmission block 7.

[0030] Specifically, combined Figure 4 As shown, the guide shell 4 includes a shell 41 fixed on the side wall of the movable mold 1 and a cover plate 42 fixed on the shell 41. A plug hole 43 with a rectangular cross section is formed between the shell 41 and the cover plate 42. The length direction of the plug hole 43 is consistent with the mold closing direction of the movable mold 1, and the opening of the plug hole 43 faces the side where the fixed mold 2 is located. A guide hole 44 is also opened through the shell 41. The guide hole 44 is set along the sliding direction of the core 3, that is, the outer end of the sliding hole 11 is coaxial with the guide hole 44 and relatively connected. The opening of the guide hole 44 faces the core 3, and the inner end of the guide hole 44 is connected with the plug hole 43. The plug block 5 is in a rectangular block shape. A strip-shaped limiting groove 52 is opened on the side of the plug block 5 along the sliding direction. A limiting pin 46 is fixed on the hole wall of the plug hole 43. The plug block 5 is slidably inserted in the plug hole 43, and the limiting pin 46 is inserted in the limiting groove 52. The push block 6 is cylindrical, and the outer peripheral wall of the inner end of the push block 6 has a boss 61 in the circumferential direction. The guide hole 44 is a circular hole, and the inner end opening of the guide hole 44 has a flared opening 441. The push block 6 is slidably inserted in the guide hole 44. The area of ​​the push plane 71 is larger than the area of ​​the flared opening 441. When the push plane 71 pushes the push block 6 outward and abuts against the wall of the insertion hole 43, the boss 61 is embedded in the flared opening 441.

[0031] The inner bottom surface of the plug hole 43 is a guide slope 45, and the end of the guide slope 45 close to the guide hole 44 is inclined in the direction away from the hole 43. The longitudinal section of the transmission block 7 is trapezoidal, and the slope of one end of the transmission block 7 is against the guide slope 45. The inner end surface of the plug block 5 is a push slope 51, and the end of the push slope 51 close to the guide hole 44 is inclined in the direction of the hole 43, and the push slope 51 is against the slope of the other end of the transmission block 7. The transmission block 7 also has a push plane 71 facing the guide hole 44, and the push plane 71 is perpendicular to the center line of the guide hole 44. The inner end surface of the push block 6 is fitted against the push plane 71, and the thickness of the transmission block 7 along the sliding direction of the push block 6 is less than the width of the plug hole 43 along the sliding direction of the push block 6. One end of the guide slope 45 close to the guide hole 44 has a pressure relief hole 47 that penetrates to the outer side of the guide shell 4 along the sliding direction of the plug block 5, so that when the plug block 5 slides inward, the air between the transmission block 7 and the hole wall of the plug hole 43 is discharged from the pressure relief hole 47, and at the same time, impurities in the plug hole 43 can also be discharged from the pressure relief hole 47 to ensure structural stability.

[0032] During injection molding, the movable mold 1 moves toward the fixed mold 2 and closes the mold. The pressure block 9 on the fixed mold 2 pushes the plug block 5 inward. The plug block 5 moves inward and acts on the inclined surface of one end of the transmission block 7 through the pushing inclined surface 51. The inclined surface of the other end of the transmission block 7 slides along the guide inclined surface 45, so that the transmission block 7 moves toward the guide hole 44. The transmission block 7 pushes the push block 6 outward through the pushing plane 71. The push block 6 pushes the core 3, so that the core 3 compresses the spring and is inserted into the cavity 12. When the mold needs to be opened after the product is formed, the movable mold 1 moves away from the fixed mold 2, the pressure block 9 releases the plug block 5, and the core 3 pushes the push block 6 back under the action of the spring. The push block 6 pushes the transmission block 7 back, and the transmission block 7 slides along the guide inclined surface 45, pushing the plug block 5 back outward to realize the core pulling of the core 3.

[0033] Embodiment 2:

[0034] The core pulling structure of the injection mold is basically the same as that of the first embodiment, except that Figure 5 As shown, a mounting groove 91 is provided on the side of the pressure block 9 facing the plug block 5, and a screw hole 92 is provided on the side of the pressure block 9 facing away from the plug block 5. The inner end of the screw hole 92 passes through the bottom surface of the mounting groove 91, and an adjusting bolt 93 is screwed into the screw hole 92. A disc spring 94 and two pads 95 are provided in the mounting groove 91. The disc spring 94 is located between the two pads 95, and when the movable mold 1 and the fixed mold 2 are closed, one pad 95 presses on the inner end of the adjusting bolt 93, and the other pad 95 presses on the outer end of the plug block 5.

[0035] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0036] Although the terms such as movable mold 1, sliding hole 11, step surface 111 are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A core-pulling structure of an injection mold, the injection mold comprising a movable mold (1) and a fixed mold (2), the core-pulling structure comprising a core (3) which is cylindrical and slides in the movable mold (1) in a transverse direction, characterized in that: A guide shell (4) is fixed on the movable mold (1), and an insert block (5), a push block (6) and a transmission block (7) are arranged in the guide shell (4). The insert block (5) is slidably arranged along the mold closing direction of the movable mold (1), one end of the insert block (5) extends out of the guide shell (4), and the fixed mold (2) can push the insert block (5) inwardly during mold closing. The push block (6) is slidably arranged along the sliding direction of the core (3), and the outer end of the push block (6) faces the core (3). 3), the transmission block (7) is located between the inner end of the insert block (5) and the inner end of the push block (6), and when the insert block (5) slides inward and pushes the transmission block (7), the transmission block (7) can push the push block (6) outward, and an elastic member (8) is provided between the core (3) and the movable mold (1), and under the action of the elastic member (8), one end of the core (3) presses against the outer end of the push block (6), and the inner end of the push block (6) presses against the transmission block (7).

2. The core-pulling structure of the injection mold according to claim 1, characterized in that: The guide shell (4) has a plug hole (43) arranged along the mold closing direction of the movable mold (1), and the opening of the plug hole (43) faces the side where the fixed mold (2) is located. The plug block (5) is slidably inserted in the plug hole (43). The guide shell (4) also has a guide hole (44) arranged along the sliding direction of the core (3), the opening of the guide hole (44) faces the core (3), and the inner end of the guide hole (44) is connected to the plug hole (43). The push block (6) is slidably inserted in the guide hole (44).

3. The core-pulling structure of the injection mold according to claim 2, characterized in that: A sliding hole (11) is provided in the movable mold (1), the inner end of the sliding hole (11) penetrates into the mold cavity (12) of the movable mold (1), and the outer end is coaxial with and opposite to the guide hole (44); the core (3) is slidably arranged in the sliding hole (11), and the axial direction of the core (3) is perpendicular to the mold closing direction of the movable mold (1).

4. The core-pulling structure of the injection mold according to claim 2 or 3, characterized in that: The inner bottom surface of the insertion hole (43) is a guiding inclined surface (45), and the end of the guiding inclined surface (45) close to the guide hole (44) is inclined in a direction away from the opening of the insertion hole (43). The transmission block (7) abuts against the guiding inclined surface (45), and the thickness of the transmission block (7) along the sliding direction of the push block (6) is smaller than the width of the insertion hole (43) along the sliding direction of the push block (6).

5. The core-pulling structure of the injection mold according to claim 4, characterized in that: The transmission block (7) has a trapezoidal longitudinal section, and the inclined surface at one end of the transmission block (7) abuts against the guide inclined surface (45), and the inclined surface at the other end abuts against the inner end of the insert block (5). The transmission block (7) also has a push plane (71) facing the guide hole (44) and perpendicular to the center line of the guide hole (44), and the inner end surface of the push block (6) abuts against the push plane (71).

6. The core-pulling structure of the injection mold according to claim 5, characterized in that: The push block (6) is cylindrical, and the outer peripheral wall of the inner end of the push block (6) is provided with a convex shoulder (61) in the circumferential direction. The guide hole (44) is a circular hole, and the inner end opening of the guide hole (44) is provided with a flared opening (441). The area of ​​the push plane (71) is larger than the area of ​​the flared opening (441). When the push plane (71) pushes the push block (6) outward and abuts against the hole wall of the insertion hole (43), the convex shoulder (61) is embedded in the flared opening (441).

7. The core-pulling structure of the injection mold according to claim 6, characterized in that: The insert block (5) is in the shape of a rectangular block, and the inner end surface of the insert block (5) is a push-up inclined surface (51), the end of the push-up inclined surface (51) close to the guide hole (44) is inclined in the direction of the hole opening of the insert hole (43), and the push-up inclined surface (51) is in contact with the inclined surface of the adjacent end of the transmission block (7).

8. The core-pulling structure of the injection mold according to claim 2 or 3, characterized in that: A limiting pin (46) is fixed on the wall of the insertion hole (43), a strip-shaped limiting groove (52) is provided on the side surface of the insertion block (5) along the sliding direction, and the limiting pin (46) is inserted into the limiting groove (52).

9. The core-pulling structure of the injection mold according to claim 1, 2 or 3, characterized in that: A pressing block (9) is fixed on the side wall of the fixed mold (2). The pressing block (9) is opposite to the outer end of the insert block (5). When the movable mold (1) and the fixed mold (2) are closed, the pressing block (9) can push the insert block (5) inward.

10. The core-pulling structure of the injection mold according to claim 9, characterized in that: The pressure block (9) is provided with a mounting groove (91) on the side facing the insert block (5), and the pressure block (9) is provided with a screw hole (92) on the side facing away from the insert block (5). The inner end of the screw hole (92) passes through the bottom surface of the mounting groove (91), and an adjusting bolt (93) is screwed into the screw hole (92). A disc spring (94) and two pads (95) are provided in the mounting groove (91), and the disc spring (94) is located between the two pads (95). When the movable mold (1) and the fixed mold (2) are closed, one pad (95) presses against the inner end of the adjusting bolt (93), and the other pad (95) presses against the outer end of the insert block (5).

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