A plastic cover injection molding mold for a rear door of an automobile and a steering long core anti-retraction mechanism thereof

Abstract

This application relates to an injection molding mold for a plastic cover part for a car rear tailgate and its steering core-pulling anti-retraction mechanism, including a driving component, a fixed base, a first slider, a T-block, and a core-pulling block. The fixed base and the driving component are fixed to the core mold. The core-pulling block is slidably disposed on the core mold along the core-pulling direction. The T-block is fixed on the first slider, which is slidably connected to the fixed base and driven by the driving component. The first slider and the core-pulling block are provided with matching guide slopes. A protrusion on the slider forms a first anti-retraction abutment surface, and the corresponding concave surface of the core-pulling block forms a first anti-retraction mating surface. The angle satisfies self-locking, preventing the slider from being pushed backward under injection pressure. When the mold is closed, the two fit together to achieve self-locking anti-retraction. The top of the core-pulling block is provided with a T-shaped guide groove, with a pre-reserved gap between it and the T-block. When the mold is opened, the slider first moves during a free stroke, and the anti-retraction surface disengages and unlocks. After reaching a preset distance, the T-block abuts against the groove wall, and then the guide slope drives the core-pulling block to pull the core, achieving unlocking before core pulling. The structure is stable and reliable.

Description

Technical Field

[0001] This invention relates to the field of molds, and in particular to an injection molding mold for a plastic cover for a car rear tailgate and its steering long core-pulling anti-reverse mechanism. Background Technology

[0002] Plastic cover for car tailgate, such as Figure 1 As shown, the mesh holes 11 need to be formed by core pulling.

[0003] Core-pulling mechanism such as Figure 2 As shown, the mold includes a fixed base 21, a sliding block 22, and a core-pulling block 33. The fixed base 21 is fixed to the core mold. The sliding block 22 slides within the fixed base 21 and is driven by a hydraulic cylinder. The core-pulling block 33 slides within the core mold 4 along the core-pulling direction. The end of the core-pulling block 33 away from the plastic part is slidably connected to the sliding block 22 along an inclined direction. During operation, the sliding block 22 is moved by the hydraulic cylinder, and the inclined surface action drives the core-pulling block 33 to complete the core-pulling and resetting actions.

[0004] However, in actual injection molding production, the internal pressure of the mold cavity is extremely high during injection molding. The high-pressure melt acts directly on the molding end face of the core-pulling block, which can easily push the core-pulling block backward in the opposite direction of core pulling. Traditional structures rely solely on the locking force of the hydraulic cylinder to resist the injection pressure. Under long-term, high-frequency production conditions, the locking force of the hydraulic cylinder is prone to attenuation and cannot stably counteract the huge cavity back pressure. This leads to frequent core-pulling block backward movement, which directly causes defects such as misalignment of the mesh holes and severe burrs on the product, significantly reducing the product qualification rate and appearance quality. Summary of the Invention

[0005] To address the issue of excessive force causing the core-pulling block to retract, this application provides an injection molding die for a plastic cover part of a car's rear tailgate and its steering-oriented long core-pulling anti-retraction mechanism.

[0006] The technical solution provided in this application for an injection molding die for a plastic cover part of a car rear tailgate and its steering long core-pulling anti-reverse mechanism is as follows:

[0007] A steering long core-pulling anti-reverse mechanism includes a driving component, a fixed base, a first slider, a T-block, and a core-pulling block. The fixed base and the driving component are both fixedly installed inside the core mold. The core-pulling block is slidably connected inside the core mold along the core-pulling direction. The T-block is detachably connected to the first slider. The first slider is slidably connected to the fixed base. The driving component is used to drive the first slider to slide.

[0008] The first slider and the core-pulling block each have matching guide slopes. The guide slope of the first slider protrudes partially on one side facing the core-pulling block and forms a first anti-retraction abutment surface. The core-pulling block has a corresponding recessed first anti-retraction mating surface. The first anti-retraction abutment surface is inclined relative to the core-pulling direction of the core-pulling block and forms a self-locking angle. This self-locking angle satisfies the requirement that when the core-pulling block is subjected to injection pressure, the component of the force borne by the first anti-retraction abutment surface in the sliding direction of the first slider cannot drive the first slider to move backward. In the mold-closed injection state, the two guide slopes of the first slider and the core-pulling block abut against each other, and the first anti-retraction abutment surface and the first anti-retraction mating surface are tightly fitted. When the first slider retracts to a preset distance, the first anti-retraction mating surface disengages from the first anti-retraction abutment surface to release the anti-retraction lock.

[0009] The top of the core-pulling block is provided with a T-shaped guide groove that matches the T-shaped block. A preset gap is left between the T-shaped guide groove and the T-shaped block in the core-pulling direction. Before the first slider retracts to a preset distance, the T-shaped block moves within the preset gap, and the core-pulling block remains stationary. When the first slider retracts to the preset distance, the T-shaped block abuts against the side wall of the T-shaped guide groove near the first slider.

[0010] By adopting the above technical solution, and by adding a first anti-retraction abutment surface and a first anti-retraction mating surface that cooperate with each other between the first slider and the core-pulling block, and ensuring that their inclination angle meets the self-locking condition, during injection molding, the injection force on the core-pulling block is converted into a clamping force perpendicular to the first anti-retraction abutment surface, rather than a component force that pushes the first slider backward, thereby achieving self-locking and anti-retraction. Structurally, this completely eliminates the backward displacement of the core-pulling block, ensuring the molding accuracy of the mesh holes and the product's appearance quality. When the mold opens, the driving component drives the first slider to make a preset distance of idle travel. The T-block slides relative to the core-pulling block within the T-shaped guide groove without moving it. At this time, the first anti-retraction abutment surface and the first anti-retraction mating surface gradually separate, releasing the anti-retraction lock. When the first slider moves to the preset distance, the T-block abuts against the side wall of the T-shaped guide groove, and then the guide inclined surface drives the core-pulling block to complete the core-pulling action, achieving an orderly movement of unlocking first and then pulling the core, resulting in a stable and reliable structure.

[0011] Preferably, in the mold-closed injection molding state, the T-block abuts against the side wall of the T-shaped guide groove away from the first slider.

[0012] By adopting the above technical solution, the space inside the T-shaped guide groove is fully utilized, making the structure more compact.

[0013] Preferably, at the tapered end of the first slider, a guide slope extends smoothly to form a second anti-recoil abutment surface. The second anti-recoil abutment surface is parallel to the first anti-recoil abutment surface and is located on opposite sides of the first slider. The core-pulling block is provided with a second anti-recoil mating surface corresponding to the position of the second anti-recoil abutment surface. In the mold-closed injection state, the second anti-recoil abutment surface and the second anti-recoil mating surface are tightly fitted. When the first slider retracts to a preset distance, the second anti-recoil mating surface disengages from the second anti-recoil abutment surface.

[0014] By adopting the above technical solution, the injection force on the core-pulling block can be more evenly distributed on the first anti-retraction contact surface and the second anti-retraction contact surface, which greatly improves the load-bearing capacity and structural strength of the anti-retraction mechanism.

[0015] Preferably, the raised portion forming the first anti-retraction contact surface on the first slider has a chamfered surface at one end near the tapered end of the first slider.

[0016] By adopting the above technical solution, the chamfered surface plays a guiding and transitioning role during the mold closing and resetting process.

[0017] A plastic injection molding mold for a car rear tailgate cover includes a steering long core-pulling anti-reverse mechanism, a core mold and a stop block. The core mold has an assembly groove, and the stop block is detachably fixed in the assembly groove. In the mold-closed injection state, the tapered end of the first slider abuts against the stop block.

[0018] By adopting the above technical solution, the first slider directly abuts against the stop block during mold closing and injection molding. The stop block provides end rigid support for the first slider, and the pushing force of the driving component on the first slider can be applied to the stop block, thereby further resisting the backward tendency of the first slider caused by the reaction force of the core-pulling block.

[0019] Preferably, it also includes a core-pulling temperature control component, which includes an inner flow channel, two guide flow channels, two cooling flow channels, two heating flow channels, and a flow channel switching component; the inner flow channel is opened inside the core-pulling block, and the two ends of the inner flow channel are respectively docking interfaces; the two guide flow channels are both opened inside the core mold, and one end of the two guide flow channels is connected to the two docking interfaces respectively; the other end of the guide flow channels is connected to the flow channel switching component.

[0020] Two cooling channels and two heating channels are all formed inside the core mold. One end of the cooling channel and the heating channel are connected to the channel switching component, the other end of the cooling channel is used to connect to the cold source, and the other end of the heating channel is used to connect to the heat source.

[0021] The block has an installation groove, the flow channel switching component is installed in the installation groove, and the block has several connecting channels. The flow channel switching component is connected to the guide flow channel, the cooling flow channel and the heating flow channel through the connecting channels. The flow channel switching component is used to control the two guide flow channels to be connected to the two cooling flow channels one-to-one, or to the two heating flow channels one-to-one.

[0022] By adopting the above technical solution, during injection molding, the heat source is connected to the inner runner via a flow channel switching component to heat the core-pulling block, matching the temperature of the molten plastic. This prevents premature cooling of the plastic due to excessively low core-pulling block temperature, which would affect the molding quality and surface finish of the mesh holes. Before and after the core-pulling action, i.e., when the long core-pulling anti-retraction mechanism unlocks but the core-pulling block remains stationary, the system switches to a cold source for rapid cooling, solidifying and setting the molded area to prevent ejection deformation. This precise temperature control strategy ensures molding quality while shortening the molding cycle.

[0023] Preferably, the flow channel switching component includes a spring, a limiting component, and a switching block. The mounting groove passes through the abutment block along a sliding direction parallel to the first slider. The switching block is slidably connected in the mounting groove along a sliding direction parallel to the first slider. A groove is formed on the side wall of the mounting groove away from the first slider. One end of the spring abuts against the inner wall of the groove, and the other end of the spring abuts against the switching block. The spring drives the switching block to move toward the first slider.

[0024] The switching block has two non-connected cooling selection channels and two heating selection channels. In the mold-closed injection state, the switching block abuts against the first slider. The two ends of the heating selection channel are respectively connected to the corresponding guide channel and the corresponding heating channel. When the first slider retracts to a preset distance, the two ends of the cooling selection channel are respectively connected to the corresponding guide channel and the corresponding cooling channel. The limiting member is used to restrict the switching block from continuing to move towards the first slider.

[0025] By adopting the above technical solution, the flow channel switching component is designed to be linked with the first slider, achieving automatic switching of the temperature control mode. During mold closing and injection molding, the first slider pushes the switching block to compress the spring during its reset, connecting the heating selection channel and heating the core-pulling block. During mold opening and core pulling, the first slider retracts, and the spring pushes the switching block to follow, until the limit component restricts its further movement. At this point, the cooling selection channel connects, automatically switching to the cooling mode. The entire process requires no additional control system or actuators, relying entirely on the mold's own opening and closing actions. It features an ingenious structure, high reliability, and low cost.

[0026] Preferably, the limiting component includes a limiting block and a limiting groove. The limiting block is fixedly mounted on the switching block, and the limiting groove is formed on the inner wall of the mounting groove. The end of the limiting groove away from the first slider passes through the abutment block. When the first slider retracts to a preset distance, the limiting block abuts against the end wall of the limiting groove.

[0027] By adopting the above technical solution, when the first slider retracts, the spring pushes the switching block to move until the limiting block abuts against the end wall of the limiting groove. At this time, the position of the switching block is precisely fixed, ensuring the accurate alignment of the cooling selection channel with the guide channel and the cooling channel, and realizing the stable connection of the cooling circuit. One end of the limiting groove passes through the abutment block, which facilitates processing and assembly.

[0028] The main technical effects of this invention are reflected in the following aspects:

[0029] 1. This invention adds a first anti-retraction contact surface and a first anti-retraction mating surface that cooperate with each other between the first slider and the core-pulling block, and makes their tilt angle meet the self-locking condition. When injection molding, the injection force on the core-pulling block is converted into a clamping force perpendicular to the direction of the first anti-retraction contact surface, rather than the component force that pushes the first slider backward, thereby achieving self-locking and anti-retraction. Structurally, it completely eliminates the backward displacement of the core-pulling block and ensures the molding accuracy of the mesh hole and the appearance quality of the product.

[0030] 2. When the mold is opened, the driving component drives the first slider to move a preset distance of idle stroke. The T-block slides relative to the core-pulling block in the T-shaped guide groove without driving the core-pulling block. At this time, the first anti-retraction contact surface and the first anti-retraction mating surface gradually separate, releasing the anti-retraction lock. When the first slider moves to the preset distance, the T-block abuts against the side wall of the T-shaped guide groove, and then the core-pulling block is driven by the guide inclined surface to complete the core-pulling action, realizing the orderly movement of unlocking first and then pulling the core. The structure is stable and reliable. Attached Figure Description

[0031] Figure 1 This is a structural diagram of the plastic cover for the rear tailgate of a car.

[0032] Figure 2 This is a schematic diagram of the core-pulling mechanism in related technologies.

[0033] Figure 3 This is a schematic diagram of the structure of the steering long core-pulling anti-reverse mechanism and the injection molded part in Embodiment 1 of this application.

[0034] Figure 4 This is a structural schematic diagram of the steering long core-pulling anti-reverse mechanism from another angle in Embodiment 1 of this application.

[0035] Figure 5 yes Figure 4 Enlarged view of point A in the middle.

[0036] Figure 6This is a schematic diagram of the cooperation between the first slider and the core-pulling block in Embodiment 1 of this application.

[0037] Figure 7 yes Figure 6 Enlarged view of point B in the middle.

[0038] Figure 8 It is along Figure 4 A cross-sectional view of the CC line.

[0039] Figure 9 This is a schematic diagram of the structure of the first slider in Embodiment 1 of this application, showing the state of release from anti-reverse locking.

[0040] Figure 10 This is a schematic diagram of the overall structure of the injection molding mold for the plastic cover of the automobile rear tailgate, which is an embodiment of this application.

[0041] Figure 11 This is a schematic diagram of the core mold structure of Embodiment 2 of this application.

[0042] Figure 12 This is a schematic diagram of the structure of the steering long core-pulling anti-reverse mechanism and the stop block in Embodiment 2 of this application.

[0043] Figure 13 It is along Figure 11 A cross-sectional view of the DD line.

[0044] Figure 14 yes Figure 13 Enlarged view of point E in the middle.

[0045] Figure 15 yes Figure 12 Enlarged view of point F in the middle.

[0046] Figure 16 This is a schematic diagram of the assembly of the switching block and the stop block in Embodiment 2 of this application.

[0047] Explanation of reference numerals in the attached drawings: 1. Injection molded part; 11. Mesh hole; 21. Fixing base; 22. Sliding block; 31. First slider; 32. T-block; 33. Core-pulling block; 34. Guide slope; 351. First anti-retraction contact surface; 352. First anti-retraction mating surface; 353. Chamfered surface; 361. Second anti-retraction contact surface; 362. Second anti-retraction mating surface; 37. T 371. Guide groove; 38. Preset gap; 4. Drive component; 4. Core mold; 41. Assembly groove; 411. Groove; 5. Abutment block; 51. Mounting groove; 52. Connecting channel; 6. Core pulling temperature control component; 61. Inner flow channel; 611. Connecting interface; 612. Waist-shaped groove; 613. Enclosing groove; 614. Sealing strip; 615. Inner channel; 62. Guide flow channel; 63. Cooling flow channel; 64. Heating flow channel; 7. Flow channel switching component; 71. Spring; 72. Switching block; 721. Heating selection channel; 722. Cooling selection channel; 73. Limiting block; 74. Limiting groove. Detailed Implementation

[0048] The following is in conjunction with the appendix Figures 1-16 This application will be described in further detail to make the technical solution of this application easier to understand and master. Example 1

[0049] This application discloses a steering long core-pulling anti-reverse mechanism.

[0050] Reference Figures 3-9 The steering long core-pulling anti-reverse mechanism of this embodiment includes a driving component 38, a fixed base 21, a first slider 31, a T-block 32, and a core-pulling block 33. The fixed base 21 and the driving component 38 are both fixedly installed in the core mold 4. The core-pulling block 33 is slidably connected in the core mold 4 along the core-pulling direction. The T-block 32 is detachably fixed to the first slider 31 by screws. The first slider 31 is slidably connected to the fixed base 21. The driving component 38 is used to drive the first slider 31 to slide.

[0051] Reference Figures 3-9 The first slider 31 and the core-pulling block 33 each have a matching guide slope 34. The guide slope 34 of the first slider 31 protrudes partially on the side facing the core-pulling block 33 and forms a first anti-retraction abutment surface 351. The core-pulling block 33 has a corresponding recessed first anti-retraction mating surface 352. The first anti-retraction abutment surface 351 is inclined relative to the core-pulling direction of the core-pulling block 33 and forms a self-locking angle. This self-locking angle satisfies that when the core-pulling block 33 is subjected to injection pressure, the force borne by the first anti-retraction abutment surface 351 in the sliding direction of the first slider 31 cannot drive the first slider 31 to move backward. In the mold-closed injection state, the two guide slopes 34 of the first slider 31 and the core-pulling block 33 abut against each other, and the first anti-retraction abutment surface 351 and the first anti-retraction mating surface 352 are tightly fitted together. When the first slider 31 retracts to a preset distance, the first anti-retraction mating surface 352 disengages from the first anti-retraction abutment surface 351 to release the anti-retraction lock.

[0052] Reference Figure 4 , Figure 5 , Figure 8 and Figure 9 The top of the core-pulling block 33 is provided with a T-shaped guide groove 37 that is adapted to the T-shaped block 32. A preset gap 371 is left between the T-shaped guide groove 37 and the T-shaped block 32 in the core-pulling direction. When the first slider 31 retracts to a preset distance, the T-shaped block 32 moves within the preset gap 371, and the core-pulling block 33 remains stationary. When the first slider 31 retracts to a preset distance, the T-shaped block 32 abuts against the side wall of the T-shaped guide groove 37 near the first slider 31.

[0053] Reference Figures 3-9By adding a first anti-retraction contact surface 351 and a first anti-retraction mating surface 352 between the first slider 31 and the core-pulling block 33, and making its tilt angle meet the self-locking condition, when injection molding, the injection force on the core-pulling block 33 is converted into a clamping force perpendicular to the first anti-retraction contact surface 351, rather than the component force that pushes the first slider 31 backward, thereby achieving self-locking and anti-retraction, completely eliminating the backward displacement of the core-pulling block 33 from the structure, and ensuring the molding accuracy of the mesh hole 11 and the product appearance quality. When the mold is opened, the driving component 38 drives the first slider 31 to move a preset distance of idle stroke. The T-block 32 slides relative to the T-shaped guide groove 37 without driving the core-pulling block 33. At this time, the first anti-retraction contact surface 351 and the first anti-retraction mating surface 352 gradually separate, releasing the anti-retraction lock. When the first slider 31 moves to the preset distance, the T-block 32 abuts against the side wall of the T-shaped guide groove 37, and then the core-pulling block 33 is driven by the guide inclined surface 34 to complete the core-pulling action, realizing the orderly movement of unlocking first and then pulling the core. The structure is stable and reliable.

[0054] Reference Figure 3 and Figure 4 The drive component 38 is preferably a two-stage hydraulic cylinder with two controllable strokes, which facilitates the intermittent unlocking and core-pulling movement of the first slider 31. Of course, a regular hydraulic cylinder can also be used, but the flow rate of hydraulic oil needs to be precisely controlled.

[0055] Reference Figure 4 and Figure 5 In the mold-closed injection state, the T-block 32 abuts against the side wall of the T-shaped guide groove 37 away from the first slider 31. This fully utilizes the space within the T-shaped guide groove 37, resulting in a more compact structure.

[0056] Reference Figure 6 At the tapered end of the first slider 31, the guide slope 34 extends smoothly to form a second anti-retraction abutment surface 361. The second anti-retraction abutment surface 361 is parallel to the first anti-retraction abutment surface 351 and is located on opposite sides of the first slider 31. The core-pulling block 33 is provided with a second anti-retraction mating surface 362 corresponding to the position of the second anti-retraction abutment surface 361. In the mold-closed injection state, the second anti-retraction abutment surface 361 and the second anti-retraction mating surface 362 are tightly fitted. When the first slider 31 retracts to a preset distance, the second anti-retraction mating surface 362 disengages from the second anti-retraction abutment surface 361.

[0057] Reference Figure 6 The injection force on the core-pulling block 33 can be more evenly distributed on the first anti-retraction contact surface 351 and the second anti-retraction contact surface 361, which greatly improves the load-bearing capacity and structural strength of the anti-retraction mechanism.

[0058] Reference Figure 6 and Figure 7A raised portion of the first anti-retraction contact surface 351 is formed on the first slider 31, and a chamfered surface 353 is provided at the end near the tapered end of the first slider 31. The chamfered surface 353 plays a guiding transition role during the mold closing and resetting process. Example 2

[0059] This application discloses an injection molding mold for a plastic cover part for a car rear tailgate.

[0060] Reference Figures 10-12 The injection molding mold for a plastic cover for a car rear tailgate in this embodiment includes a steering long core pulling anti-reverse mechanism, a core mold 4 and a stop block 5. The core mold 4 has an assembly groove 41, and the stop block 5 is detachably fixed in the assembly groove 41 by screws. In the mold-closed injection state, the tapered end of the first slider 31 abuts against the stop block 5.

[0061] Reference Figures 10-12 During injection molding, the first slider 31 directly abuts against the abutment block 5, and the abutment block 5 provides end rigid support for the first slider 31. The pushing force of the drive component 38 on the first slider 31 can be applied to the abutment block 5, thereby further resisting the backward tendency of the first slider 31 caused by the reaction force of the core-pulling block 33.

[0062] Reference Figures 11-15 It also includes a core-pulling temperature control component 6, which includes an inner flow channel 61, two guide flow channels 62, two cooling flow channels 63, two heating flow channels 64, and a flow channel switching component 7. The inner flow channel 61 is opened in the core-pulling block 33, and the two ends of the inner flow channel 61 are respectively interface 611. The two guide flow channels 62 are both opened in the core mold 4, and one end of the two guide flow channels 62 is connected to the two interface 611 respectively, and the other end of the guide flow channel 62 is connected to the flow channel switching component 7.

[0063] Reference Figures 11-15 Two cooling channels 63 and two heating channels 64 are all formed inside the core mold 4. One end of the cooling channel 63 and the heating channel 64 is connected to the channel switching component 7, and the other end of the cooling channel 63 is used to connect to a cold source, and the other end of the heating channel 64 is used to connect to a heat source. The two cooling channels 63 need to be kept in a one-in-one-out configuration so that the cold source can continuously pass through the inner channel 61 to cool the core-pulling block 33; similarly, the two heating channels 64 allow the heat source to continuously pass through the inner channel 61 to preheat the core-pulling block 33.

[0064] Reference Figures 11-16The abutment block 5 has an installation groove 51, and the flow channel switching component 7 is installed in the installation groove 51. The abutment block 5 has several connecting channels 52. The flow channel switching component 7 is connected to the guide flow channel 62, the cooling flow channel 63 and the heating flow channel 64 through the connecting channels 52 respectively. The flow channel switching component 7 is used to control the two guide flow channels 62 to be connected to the two cooling flow channels 63 in a one-to-one correspondence, or to the two heating flow channels 64 in a one-to-one correspondence.

[0065] Reference Figures 11-16 During injection molding, the heat source is connected to the inner runner 61 via the runner switching component 7 to heat the core-pulling block 33, matching the temperature of the molten plastic. This prevents premature cooling of the plastic due to excessively low temperature of the core-pulling block 33, which would affect the molding quality and surface finish of the mesh holes 11. Before and after the core-pulling action, i.e., when the long core-pulling anti-retraction mechanism is unlocked but the core-pulling block 33 remains stationary, the system switches to a cold source to rapidly cool the core-pulling block 33, solidifying and setting the molded area to prevent ejection deformation. This precise temperature control strategy ensures molding quality while shortening the molding cycle.

[0066] Reference Figures 11-16 The flow channel switching component 7 includes a spring 71, a limiting component, and a switching block 72. The mounting groove 51 passes through the abutment block 5 along the sliding direction parallel to the first slider 31. The switching block 72 is slidably connected in the mounting groove 51 along the sliding direction parallel to the first slider 31. A groove 411 is provided on the side wall of the mounting groove 41 away from the first slider 31. One end of the spring 71 abuts against the inner wall of the groove 411, and the other end of the spring 71 abuts against the switching block 72. The spring 71 drives the switching block 72 to move toward the first slider 31.

[0067] Reference Figures 11-16 The switching block 72 has two non-connected cooling selection channels 722 and two heating selection channels 721. In the mold-closed injection state, the switching block 72 abuts against the first slider 31. The two ends of the heating selection channel 721 are respectively connected to the corresponding guide channel 62 and the corresponding heating channel 64. When the first slider 31 retracts to a preset distance, the two ends of the cooling selection channel 722 are respectively connected to the corresponding guide channel 62 and the corresponding cooling channel 63. The limiting member is used to restrict the switching block 72 from continuing to move toward the first slider 31.

[0068] Reference Figures 11-16The flow channel switching component 7 is designed to be linked with the first slider 31, enabling automatic switching of the temperature control mode. During mold closing and injection molding, the first slider 31 pushes the switching block 72 to compress the spring 71 during its reset process, connecting the heating selection channel 721 to heat the core-pulling block 33. During mold opening and core pulling, the first slider 31 retracts, and the spring 71 pushes the switching block 72 to follow, until the limit component restricts its further movement. At this time, the cooling selection channel 722 connects, automatically switching to the cooling mode. The entire process requires no additional control system or actuators, relying entirely on the mold's own opening and closing actions. It features an ingenious structure, high reliability, and low cost.

[0069] Reference Figure 16 The limiting component includes a limiting block 73 and a limiting groove 74. The limiting block 73 is fixedly mounted on the switching block 72, and the limiting groove 74 is opened on the inner wall of the mounting groove 51. The end of the limiting groove 74 away from the first slider 31 passes through the abutment block 5. When the first slider 31 retracts to a preset distance, the limiting block 73 abuts against the end wall of the limiting groove 74.

[0070] Reference Figure 14 and Figure 16 When the first slider 31 retracts, the spring 71 pushes the switching block 72 to move until the limiting block 73 abuts against the end wall of the limiting groove 74. At this time, the position of the switching block 72 is precisely fixed, ensuring the precise alignment of the cooling selection channel 722 with the guide channel 62 and the cooling channel 63, and realizing the stable connection of the cooling circuit. One end of the limiting groove 74 passes through the abutment block 5, which facilitates processing and assembly.

[0071] Reference Figures 11-16 The inner flow channel 61 is composed of multiple inner channels 615 formed within the core-pulling block 33. The corresponding ends of the inner channels 615 are sealed with metal plugs, making the inner flow channel 61 a unidirectional flow channel structure. The two interfaces 611 are the inlet and outlet, respectively. Since the core-pulling block 33 moves a fixed stroke during core pulling or resetting, a waist-shaped groove 612 needs to be formed at the interface 611 along the direction of movement. The waist-shaped groove 612 always remains in communication with the guide flow channel 62. In order to improve the sealing performance at the joint between the guide flow channel 62 and the waist-shaped groove 612, a surrounding groove 613 is formed on the outside of the core-pulling block 33 located in the waist-shaped groove 612. A sealing strip 614 is glued and fixed inside the surrounding groove 613. The sealing strip 614 always presses against the corresponding inner wall of the guide flow channel 62 during the movement of the core-pulling block 33. Similarly, to ensure the sealing effect of the flow channel, a sealing element adapted to the above-mentioned sealing strip structure is also provided at the mating surface of the switching block 72 and the abutment block 5.

[0072] Reference Figure 10 The injection molding mold for the plastic cover of the rear tailgate of an automobile also includes cavity mold, ejection mechanism and conventional core pulling mechanism, which will not be described in detail here.

[0073] Of course, the above are just typical examples of this application. In addition, this application may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed in this application.

Claims

1. An injection molding tool for a plastic cover for a tailgate of an automobile, characterized in that: The device includes a core mold, a stop block, and a steering long core-pulling anti-retraction mechanism. The steering long core-pulling anti-retraction mechanism includes a driving component, a fixed base, a first slider, a T-block, and a core-pulling block. The fixed base and the driving component are both fixedly installed inside the core mold. The core-pulling block is slidably connected inside the core mold along the core-pulling direction. The T-block is detachably connected to the first slider. The first slider is slidably connected to the fixed base. The driving component is used to drive the first slider to slide. The first slider and the core-pulling block each have matching guide slopes. The guide slope of the first slider protrudes partially on one side facing the core-pulling block and forms a first anti-retraction abutment surface. The core-pulling block has a corresponding recessed first anti-retraction mating surface. The first anti-retraction abutment surface is inclined relative to the core-pulling direction of the core-pulling block and forms a self-locking angle. This self-locking angle satisfies the requirement that when the core-pulling block is subjected to injection pressure, the component of the force borne by the first anti-retraction abutment surface in the sliding direction of the first slider cannot drive the first slider to move backward. In the mold-closed injection state, the two guide slopes of the first slider and the core-pulling block abut against each other, and the first anti-retraction abutment surface and the first anti-retraction mating surface are tightly fitted. When the first slider retracts to a preset distance, the first anti-retraction mating surface disengages from the first anti-retraction abutment surface to release the anti-retraction lock. The top of the core-pulling block is provided with a T-shaped guide groove that matches the T-shaped block. A preset gap is left between the T-shaped guide groove and the T-shaped block in the core-pulling direction. When the first slider retracts to a preset distance, the T-shaped block moves within the preset gap, and the core-pulling block remains stationary. When the first slider retracts to the preset distance, the T-shaped block abuts against the side wall of the T-shaped guide groove near the first slider. The core mold has an assembly groove, and the abutment block is detachably fixed in the assembly groove. In the mold-closed injection state, the tapered end of the first slider abuts against the abutment block. It also includes a core-pulling temperature control component, which includes an inner flow channel, two guide flow channels, two cooling flow channels, two heating flow channels, and a flow channel switching component. The inner flow channel is opened inside the core-pulling block, and the two ends of the inner flow channel are mating interfaces. The two guide flow channels are both opened inside the core mold, and one end of each guide flow channel is connected to one of the two mating interfaces. The other end of each guide flow channel is connected to the flow channel switching component. Two cooling channels and two heating channels are all formed inside the core mold. One end of the cooling channel and the heating channel are connected to the channel switching component, the other end of the cooling channel is used to connect to the cold source, and the other end of the heating channel is used to connect to the heat source. The block has an installation groove, the flow channel switching component is installed in the installation groove, and the block has several connecting channels. The flow channel switching component is connected to the guide flow channel, the cooling flow channel and the heating flow channel through the connecting channels. The flow channel switching component is used to control the two guide flow channels to be connected to the two cooling flow channels one-to-one, or to the two heating flow channels one-to-one.

2. The injection molding mold for a plastic cover for a car rear tailgate according to claim 1, characterized in that: In the mold-closed injection molding state, the T-block abuts against the side wall of the T-shaped guide groove away from the first slider.

3. The injection molding die for a plastic cover of a tailgate of an automobile according to claim 1, wherein: At the tapered end of the first slider, a guide slope extends smoothly to form a second anti-recoil abutment surface. The second anti-recoil abutment surface is parallel to the first anti-recoil abutment surface and is located on opposite sides of the first slider. The core-pulling block is provided with a second anti-recoil mating surface corresponding to the position of the second anti-recoil abutment surface. In the mold-closed injection state, the second anti-recoil abutment surface and the second anti-recoil mating surface are tightly fitted. When the first slider retracts to a preset distance, the second anti-recoil mating surface disengages from the second anti-recoil abutment surface.

4. The injection molding tool for a plastic cover of a tailgate of a vehicle according to claim 1, wherein: The first slider has a raised portion forming a first anti-retraction contact surface, and a chamfered surface is provided at one end near the tapered end of the first slider.

5. The injection molding die for a plastic cover of a tailgate of an automobile according to claim 1, wherein: The flow channel switching component includes a spring, a limiting component, and a switching block. The mounting groove passes through the abutment block along the sliding direction parallel to the first slider. The switching block is slidably connected in the mounting groove along the sliding direction parallel to the first slider. A groove is provided on the side wall of the mounting groove away from the first slider. One end of the spring abuts against the inner wall of the groove, and the other end of the spring abuts against the switching block. The spring drives the switching block to move toward the first slider. The switching block has two non-connected cooling selection channels and two heating selection channels. In the mold-closed injection state, the switching block abuts against the first slider. The two ends of the heating selection channel are respectively connected to the corresponding guide channel and the corresponding heating channel. When the first slider retracts to a preset distance, the two ends of the cooling selection channel are respectively connected to the corresponding guide channel and the corresponding cooling channel. The limiting member is used to restrict the switching block from continuing to move towards the first slider.

6. The injection molding tool for a plastic cover of a tailgate of a vehicle according to claim 5, characterized in that: The limiting component includes a limiting block and a limiting groove. The limiting block is fixedly mounted on the switching block, and the limiting groove is formed on the inner wall of the mounting groove. The end of the limiting groove away from the first slider passes through the abutment block. When the first slider retracts to a preset distance, the limiting block abuts against the end wall of the limiting groove.

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