Ejection structure for a mold

Abstract

The application relates to an ejection structure for a mold, belonging to the technical field of injection molds, which comprises: an inclined ejector that slides along the length direction of a guide groove in a back mold; a butterfly spring arranged in the guide groove and arranged in the length direction of the guide groove in the axial direction; and a nitrogen spring slidingly connected in the guide groove, with the cylinder end of the nitrogen spring abutting against one side of the butterfly spring away from the bottom wall of the guide groove, the piston rod of the nitrogen spring extending along the length direction of the guide groove, and the piston rod end of the nitrogen spring being fixed to the bottom of the inclined ejector. The application has the effect of prolonging the service life of the nitrogen spring in the mold.

Description

Technical Field

[0001] This application relates to the field of injection mold technology, and in particular to an ejection structure for a mold. Background Technology

[0002] Injection molding is a common method for processing plastic products, especially for producing parts with complex shapes. It involves injecting molten plastic material into a mold cavity formed by a front mold and a rear mold, and then cooling and solidifying it to obtain the molded product.

[0003] Demolding is the final step in the injection molding process, and the quality of demolding ultimately determines the quality of the molded part. During demolding, it is necessary to overcome the friction between the workpiece and the mold, atmospheric pressure, and the friction of the mold mechanism itself. Therefore, different demolding mechanisms are used for different types of workpieces to achieve separation between the mold and the workpiece.

[0004] An injection-molded part containing an undercut, as shown in the reference. Figure 1 An injection molded workpiece containing undercuts includes a workpiece body 0, on which a plurality of undercuts 01 are provided. The figure shows three undercuts as an example. Each undercut 01 has a connecting hole 02.

[0005] For the aforementioned injection molded workpiece containing undercuts, a slanted ejector 1 is provided at the position of undercut 01 in the rear mold 3, as shown in the reference. Figure 2 A type of angled ejector 1 includes an abutment block 11, on which a through block 111 is provided. A replacement bolt 112 is threaded onto the through block 111, and the through block 111 is fixed to the abutment block 11 by the replacement bolt 112 to facilitate the replacement of the through block 111. A guide groove 25 is provided on the rear mold 3 at the position corresponding to the angled ejector 1. A nitrogen spring 15 is provided on the bottom wall of the guide groove 25, and the angled ejector 1 is located at the end of the nitrogen spring 15 away from the guide groove 25.

[0006] During mold closing, the rear mold 3 moves towards the front mold until it engages with the front mold. At this time, the through block 111 abuts against the front mold, forming a casting cavity at the workpiece undercut 01 position between the abutting block 11 and the front mold, and the nitrogen spring 15 is compressed. During injection molding, slurry is poured into the mold, forming the undercut 01 at the abutting block 11 and the connecting hole 02 at the through block 111. During mold opening, the rear mold 3 moves away from the front mold to separate the rear mold 3 from the workpiece. In this process, the inclined ejector 1 first moves away from the workpiece under the drive of the rear mold 3. Under the action of the elastic force of the nitrogen spring 15, the inclined ejector 1 moves towards the workpiece first. During the initial time of mold opening, the inclined ejector 1 always moves relative to the rear mold 3 towards the front mold and presses against the workpiece. When the nitrogen spring 15 returns to its initial state, the inclined ejector 1 no longer moves relative to the rear mold 3 towards the front mold, but remains relatively stationary with the rear mold 3 and moves away from the front mold with the rear mold 3, thus completing the demolding. Because the shape of the rear mold 3 is relatively rugged, the friction between the rear mold 3 and the workpiece is relatively large. Therefore, a nitrogen spring 15 is added during the separation process of the rear mold 3 and the workpiece. In the initial process of demolding, the nitrogen spring 15 uses its elasticity to fix the workpiece on the front mold, thereby facilitating the separation of the rear mold 3 and the workpiece. Furthermore, the nitrogen spring 15 can provide a stable force output, making the force of the inclined ejector 1 against the workpiece uniform.

[0007] Regarding the aforementioned technologies, the inventors believe that because the inclined ejector 1 is in close contact with the front mold during the mold closing process, and the inclined ejector 1 is tightly pressed into the guide groove 25, at the moment of mold opening, the nitrogen spring 15 needs to release a large elastic force to push the inclined ejector 1 out of the guide groove 25, suddenly releasing the elastic potential energy accumulated in the nitrogen spring 15, causing the nitrogen spring 15 to be subjected to a large impact force, resulting in deformation, damage or fatigue of the spring, thereby drastically reducing the service life of the nitrogen spring 15. Summary of the Invention

[0008] In order to extend the service life of nitrogen springs in molds, this application provides an ejection structure for molds.

[0009] The ejection structure for a mold provided in this application adopts the following technical solution:

[0010] An ejection structure for a mold, comprising:

[0011] The inclined ejector slides along the length of the guide groove inside the rear mold.

[0012] A disc spring is installed in a guide groove, with its axial direction along the length of the guide groove.

[0013] A nitrogen spring is slidably connected inside the guide groove. Its cylinder end abuts against the side of the disc spring away from the bottom wall of the guide groove. Its piston rod extends along the length of the guide groove, and its piston rod end is fixedly connected to the bottom of the inclined top.

[0014] By adopting the above technical solution, during mold closing, the rear mold moves towards the front mold until it engages with the front mold. At this time, the through block abuts against the front mold, forming a casting cavity at the undercut position of the workpiece between the abutting block and the front mold. The nitrogen spring and the disc spring are compressed. During the compression process, the inclined ejector slides along the axial direction of the protective cover towards the second pad, and the bottom of the protective cover slides along the axial direction of the guide post towards the second pad. During injection molding, slurry is poured into the mold. The slurry forms an undercut at the abutting block, and a connecting hole for the workpiece is formed at the through block.

[0015] During mold opening, the rear mold moves away from the front mold to separate the rear mold from the workpiece. In this process, the ejector pin moves away from the workpiece first under the drive of the rear mold. At the moment of mold opening, the butterfly spring and the nitrogen spring release elastic potential energy together, pushing the ejector pin towards the front mold. The elastic force released instantaneously by the butterfly spring assists the nitrogen spring in pushing the ejector pin towards the front mold, avoiding the situation where the nitrogen spring alone pushes the ejector pin out at the moment of mold opening, causing the nitrogen spring to be subjected to a large impact force due to the sudden release of the accumulated elastic potential energy, which would damage the nitrogen spring. The butterfly spring can play a good auxiliary role for the nitrogen spring, extending the service life of the nitrogen spring in the mold.

[0016] Furthermore, because the through-block in the aforementioned structure needs to be pressed against the front mold during mold closing, its end face is subjected to significant impact force, making it prone to damage. Therefore, the through-block needs to be replaced periodically to ensure a tight fit between it and the front mold, reducing the likelihood of injection molding slurry entering between them and guaranteeing the quality of the injection molded part. When the through-block needs replacement, simply unscrew the replacement bolts to replace it, and then secure the through-block to the angled ejector using the replacement bolts.

[0017] In the aforementioned structure, the disc spring is subjected to immense compressive force each time the mold closes, and upon mold opening, it releases its accumulated elastic potential energy all at once, resulting in a tremendous impact force. Both of these processes significantly shorten the lifespan of the disc spring. In this structure, however, the protective cover can be removed from the guide groove along the axial direction of the guide post, making it easier to replace the disc spring.

[0018] Optional, including:

[0019] The protective cover has a cylinder for the nitrogen spring fixed inside it. The piston rod of the nitrogen spring slides along the length of the protective cover. The axial direction of the protective cover is set along the length of the guide groove. The inclined top is sleeved on the end of the protective cover and slides along the outer wall of the protective cover and along the axial direction of the protective cover.

[0020] The butterfly spring is located at the end of the protective cover away from the inclined top, and the protective cover slides along the length of the guide groove.

[0021] By adopting the above technical solution, on the one hand, the protective cover can separate the nitrogen spring from the butterfly spring, preventing the butterfly spring from directly acting on the nitrogen spring, reducing the impact on the nitrogen spring, and further protecting the nitrogen spring; on the other hand, the protective cover guides the movement process of the inclined jack, making the process of the inclined jack pushing forward and retracting backward more stable.

[0022] Optional, including:

[0023] Pad 1 is attached to the bottom wall of the protective cover.

[0024] The second pad is located on the side of the first pad away from the protective cover, and the butterfly spring is located between the second pad and the first pad.

[0025] When the guide post is installed on the second pad, its axial direction is set along the length of the guide groove, and its relative position with the second pad is fixed. The bottom of the first pad slides along the axial direction of the guide post.

[0026] By adopting the above technical solution, the guide column guides the movement of the protective cover, thereby making the movement of the protective cover more stable when it is pushed up by the elastic force of the butterfly spring or when it is compressed towards the butterfly spring.

[0027] Optional, including:

[0028] A positioning bolt is connected to the second pad, a butterfly spring is sleeved on the outside of the positioning bolt, a guide post is fixed to the end of the positioning bolt, and the diameter of the positioning bolt is larger than the diameter of the guide post.

[0029] By adopting the above technical solution, on the one hand, it is convenient to replace the guide post and realize the connection and separation between the guide post and the pad block 2. On the other hand, since the diameter of the positioning bolt is larger than the diameter of the guide post, the distance that the protective cover can move in the direction of the disc spring can be limited by the end face of the positioning bolt.

[0030] Optional, including:

[0031] The straight ejector is slidably connected to the rear mold, and the guide groove is set inside the straight ejector. When the mold is closed, a casting cavity for the workpiece is formed between the straight ejector and the front mold.

[0032] A sliding plate is slidably connected to the rear mold, and the direction of movement of the sliding plate is perpendicular to the direction of movement of the rear mold;

[0033] The drive rod is inclinedly set inside the rear mold and slides between it and the sliding plate.

[0034] Inclined groove, formed on sliding plate, with its bottom wall inclined;

[0035] When the rear mold drives the drive rod to move away from the front mold, the sliding plate slides along the rear mold, and the straight ejector slides along the length of the inclined groove to a position away from the front mold, causing the straight ejector to detach from the workpiece.

[0036] By adopting the above technical solution, multiple angled ejectors are connected together on a single straight ejector, enabling demolding to proceed in the order of rear mold, straight ejector, and angled ejector, or straight ejector, rear mold, and angled ejector during mold opening. This further refines the demolding process, making it easier to separate the rear mold from the workpiece and making the demolding process more meticulous, thus reducing wear on the workpiece.

[0037] Optional, including:

[0038] The limiting plate is slidably connected inside the rear mold and its position relative to the front mold remains unchanged during the mold opening and closing process. The sliding plate slides on the surface of the limiting plate.

[0039] By adopting the above technical solution, the position of the limiting plate relative to the front mold remains unchanged throughout the entire mold opening and closing process, thus allowing relative movement between it and the rear mold during mold opening. The limiting plate achieves two objectives: firstly, maintaining the distance between the sliding plate and the front mold during mold opening; secondly, allowing it to slide relative to the rear mold, thus avoiding interference with the movement of the rear mold.

[0040] Optional, including:

[0041] The positioning plate is set at a position on the rear mold away from the front mold. The positioning plate remains fixed during the mold opening and closing process, and the positioning plate is fixedly connected to the limiting plate.

[0042] By adopting the above technical solution, the positioning plate supports the limiting plate, thereby maintaining the position of the limiting plate.

[0043] Optional, including:

[0044] The adjusting plate is slidably connected to the side of the positioning plate and moves towards or away from the side of the rear mold during movement.

[0045] The drive rack is fixed on the side of the adjusting plate near the rear mold;

[0046] The drive gear is rotatably connected to the side of the rear mold and meshes with the drive rack.

[0047] Driven wheel one is fixed to the side of the drive gear and rotates synchronously with the drive gear;

[0048] The driven rack is fixed to the end of the drive rod and slides along the inner wall of the rear mold, and its sliding direction is in the same direction as the movement direction of the rear mold;

[0049] The driven gear is rotatably connected to the rear mold and meshes with the driven rack.

[0050] Driven wheel two is fixed to the side of the driven gear and rotates synchronously with the driven gear;

[0051] The belt is tensioned outside driven pulley one and driven pulley two.

[0052] By adopting the above technical solution, when the drive rack and drive gear mesh, the rear mold drives the drive gear to rotate as it moves away from the front mold. Driven wheel one rotates synchronously with the drive gear and transmits the rotation to driven wheel two through the belt. Driven wheel two drives the driven gear to rotate, which in turn drives the driven rack to move along the rear mold away from the front mold. This causes the drive rod to move away from the front mold relative to the rear mold while following the movement of the rear mold, so that the speed at which the straight ejector moves away from the workpiece is greater than the speed at which the rear mold moves away from the straight ejector. This causes the straight ejector to disengage from the workpiece first, and then the rear mold to disengage from the workpiece.

[0053] Optional, including:

[0054] A clearance groove is provided at the position of the drive gear in the rear mold;

[0055] The adjusting block slides along the inner wall of the relief groove;

[0056] When the insertion rod slides along the side of the positioning plate and is inserted between the relief groove and the adjusting block, the adjusting block and the drive gear engage with each other.

[0057] By adopting the above technical solution, when the adjusting plate moves away from the rear mold to disengage the drive gear and drive rack, the insertion rod, driven by the left and right helical screws, inserts between the adjusting block and the clearance groove, thereby pushing the adjusting block towards the drive gear and engaging it with the drive gear, thus preventing the drive gear from rotating during the movement of the rear mold. In this mode, the relative position of the drive rod to the rear mold remains unchanged during the mold opening process. Attached Figure Description

[0058] Figure 1 This is a schematic diagram of the overall structure of "an injection molded workpiece with an undercut" in the background art of this application.

[0059] Figure 2 This is a schematic diagram of the overall structure of "a type of sloping roof" in the background art of this application.

[0060] Figure 3 This is a schematic diagram of the overall structure of Embodiment 1 of this application.

[0061] Figure 4 This is a cross-sectional view of Embodiment 1 of this application, taken to highlight the disc spring.

[0062] Figure 5This is a schematic diagram of Embodiment 2 of this application, made to highlight the inclined groove.

[0063] Figure 6 yes Figure 5 Enlarged view of part A in the image.

[0064] Figure 7 yes Figure 5 Enlarged view of part B in the image.

[0065] Figure 8 This is a schematic diagram made to highlight the positioning plate in Embodiment 2.

[0066] Figure 9 This is a schematic diagram made to highlight the limiting plate in Embodiment 2.

[0067] Figure 10 This is a schematic diagram in Embodiment 3 to highlight the adjustment plate.

[0068] Figure 11 This is an enlarged view of Example 3 to highlight the left and right lead screws.

[0069] Figure 12 yes Figure 10 Enlarged view of section C in the image.

[0070] Figure 13 This is a schematic diagram made to highlight the belt in Example 3.

[0071] Figure 14 yes Figure 13 Enlarged view of part D in the image.

[0072] Figure 15 yes Figure 13 Enlarged view of part E in the image.

[0073] Figure 16 This is a schematic diagram of Embodiment 3 of this application, made to highlight the clearance groove.

[0074] Explanation of reference numerals in the attached drawings: 0. Workpiece body; 01. Undercut; 02. Connecting hole; 1. Sloping top; 11. Abutting block; 111. Through block; 112. Replacement bolt; 12. Second pad; 121. Positioning bolt; 122. Guide post; 13. Protective cover; 14. Butterfly spring; 15. Nitrogen spring; 16. Groove; 17. Fixing bolt; 18. First pad; 2. Straight top; 21. Top block; 22. Connecting post; 221. T-shaped slider; 23. Sliding plate; 231. Baffle; 232. Sloping groove; 24. Drive rod; 25. Guide groove; 3. Rear 31. Mold; 31. Limiting plate; 311. Slide groove; 312. Slide rod; 32. Positioning plate; 321. Support rod; 4. Adjusting plate; 41. Sliding block one; 42. Sliding groove; 43. Left and right helical screw; 44. Drive motor; 5. Drive rack; 51. Drive gear; 52. Rotating shaft one; 53. Driven wheel one; 54. Driven rack; 55. Rotating shaft two; 56. Driven gear; 57. Driven wheel two; 58. Belt; 6. Relief groove; 61. Adjusting block; 62. Adjusting assembly; 621. Connecting rod; 622. Sliding block two; 623. Insertion rod. Detailed Implementation

[0075] The following is in conjunction with the appendix Figure 3-16 This application will be described in further detail.

[0076] Example 1:

[0077] Embodiment 1 of this application discloses an ejection structure for a mold. (Refer to...) Figure 3 An ejection structure for a mold includes an inclined ejector 1, the inclined ejector 1 includes an abutment block 11, the abutment block 11 is provided with a through block 111, and a replacement bolt 112 is threadedly connected to the through block 111. The through block 111 is fixed to the abutment block 11 by the replacement bolt 112 so as to facilitate the replacement of the through block 111.

[0078] Reference Figure 4The bottom wall of the guide groove 25 is connected to a pad 18 and a pad 2 12. The shape of the pad 2 12 is adapted to the guide groove 25. The figure uses a cylindrical pad 2 12 as an example. The axial direction of the pad 2 12 is set along the length of the guide groove 25. A positioning bolt 121 is fixedly connected inside the pad 2 12. One end of the positioning bolt 121 protrudes from the middle of the bottom of the pad 2 12 towards the pad 18. The other end of the positioning bolt 121 protruding from the top of the pad 2 12 is fixedly connected to a guide post 122. The axial direction of the guide post 122 is set along the length of the guide groove 25. The guide post 122 slides on the pad 1 18. A protective cover 13 is provided inside the guide groove 25. The axial direction of the protective cover 13 is set along the length of the guide groove 25. The pad 1 18 is fixed to the bottom of the protective cover 13. The pad 1 18 and the protective cover 13 slide along the axial direction of the guide post 122. The diameter of the positioning bolt 121 is larger than the diameter of the guide post 122, and the end face of the positioning bolt 121 limits the distance that the first pad 18 can move in the direction of the second pad 12.

[0079] A butterfly spring 14 is fixed between pad 2 12 and pad 18. The butterfly spring 14 is sleeved outside the positioning bolt 121. The axial direction of the butterfly spring 14 is set along the length direction of the guide groove 25. One side of the butterfly spring 14 abuts against pad 2 12, and the other side of the butterfly spring 14 abuts against pad 18. A nitrogen spring 15 is installed inside the protective cover 13. The axial direction of the nitrogen spring 15 is set along the axial direction of the protective cover 13. The cylinder of the nitrogen spring 15 is fixedly connected to the protective cover 13. The piston rod of the nitrogen spring 15 extends to the outside of the protective cover 13 along the length direction of the guide groove 25, and the piston rod is slidably connected to the protective cover 13. The bottom of the inclined top 1 is sleeved on the end of the protective cover 13 away from the butterfly spring 14. The inclined top 1 slides along the outer wall of the protective cover 13 and along the axial direction of the protective cover 13. The protective cover 13 guides the movement of the inclined top 1, thereby making the movement of the inclined top 1 more stable. A groove 16 is provided at the end of the inclined top 1 away from the butterfly spring 14. The length direction of the groove 16 extends along the length direction of the guide groove 25. A fixing bolt 17 is provided in the groove 16. The end of the fixing bolt 17 passes through the inclined top 1 and is threaded to the end of the piston rod to fix the inclined top 1 and the piston rod.

[0080] The implementation principle of the ejection structure for a mold in Embodiment 1 of this application is as follows:

[0081] When the mold is closed, the rear mold 3 moves towards the front mold until the rear mold 3 engages with the front mold. At this time, the through block 111 abuts against the front mold, and the abutting block 11 and the front mold form a casting cavity at the workpiece undercut 01 position. The nitrogen spring 15 and the butterfly spring 14 are compressed. During the compression process, the inclined ejector 1 slides along the axial direction of the protective cover 13 towards the direction of the second pad 12, and the first pad 18 slides along the axial direction of the guide post 122 towards the direction of the second pad 12.

[0082] During injection molding, grout is poured into the mold. The grout forms an undercut 01 at the abutment block 11 and a connecting hole 02 for the workpiece at the through block 111.

[0083] During mold opening, the rear mold 3 moves away from the front mold to separate the rear mold 3 from the workpiece. In this process, the inclined ejector 1 moves away from the workpiece first under the drive of the rear mold 3. At the moment of mold opening, the butterfly spring 14 and the nitrogen spring 15 release elastic potential energy together, pushing the inclined ejector 1 towards the front mold. The elastic force released by the butterfly spring 14 at the moment of mold opening assists the nitrogen spring 15 in pushing the inclined ejector 1 towards the front mold, avoiding the situation where the nitrogen spring 15 alone pushes the inclined ejector 1 out at the moment of mold opening, causing the nitrogen spring 15 to be subjected to a large impact force due to the sudden release of the accumulated elastic potential energy, which would damage the nitrogen spring 15. The butterfly spring 14 can play a certain auxiliary role for the nitrogen spring 15, extending the service life of the nitrogen spring 15 in the mold.

[0084] Furthermore, because the through block 111 in the aforementioned structure needs to be pressed against the front mold during mold closing, the end face of the through block 111 is subjected to a large impact force during mold closing, making the end face of the through block 111 prone to damage. Therefore, the through block 111 needs to be replaced periodically to ensure that the through block 111 and the front mold always maintain a tight fit, reducing the probability of injection slurry entering between the through block 111 and the front mold, and ensuring the quality of the injection molded part. When the through block 111 needs to be replaced, simply unscrew the replacement bolt 112 to replace the through block 111, and then fix the through block 111 to the inclined ejector 1 using the replacement bolt 112.

[0085] In the aforementioned structure, the disc spring 14 is subjected to immense compressive force each time the mold closes, and upon mold opening, it releases its accumulated elastic potential energy all at once, resulting in a tremendous impact force. Both of these processes significantly shorten the service life of the disc spring 14. In this structure, however, the disc spring 14 can be easily replaced by removing the protective cover 13 from the guide groove 25 along the axial direction of the guide post 122.

[0086] Example 2:

[0087] Embodiment 2 of this application discloses an ejection structure for a mold. (Refer to...) Figure 5 The difference in one embodiment of the ejection structure for a mold is that it also includes a straight ejector 2, which includes an ejector block 21, a connecting column 22 and a sliding plate 23 in sequence along the direction from the front mold to the rear mold 3.

[0088] Reference Figure 6 The top block 21 is located at the position of the inclined top 1, the guide groove 25 is located inside the top block 21, and the corresponding inclined top 1 is located at the corresponding position of the guide groove 25.

[0089] Reference Figure 5 The top side shape of the ejector block 21 is adapted to the shape of the workpiece to be injected. When the mold is closed, the ejector block 21 moves towards the front mold under the drive of the rear mold 3, and forms a casting cavity for the workpiece between the ejector block 21 and the front mold. The axial direction of the connecting pillar 22 is parallel to the movement direction of the rear mold 3. There are multiple connecting pillars 22. Here, two pillars are used as an example for description.

[0090] Reference Figure 7 The sliding plate 23 and the rear mold 3 are connected by a sliding connection. The movement direction of the sliding plate 23 is perpendicular to the movement direction of the rear mold 3. A sinkhole is formed on the top of the sliding plate 23. Multiple sinkholes are provided, the specific number of which is the same as the number of connecting columns 22. Therefore, this embodiment only describes two columns as an example. The side walls of the sliding plate 23 corresponding to the sinkhole are connected to baffles 231 by bolts. The baffles 231 on both sides of the sinkhole and the sinkhole form an inclined groove 232. The bottom wall of the inclined groove 232 is inclined. A T-shaped slider 221 is fixed at the end of the connecting column 22 away from the top block 21. The T-shaped slider 221 is set in the inclined groove 232, and the side of the T-shaped slider 221 closest to the bottom wall of the inclined groove 232 is inclined and fits against the bottom wall of the inclined groove 232. The T-shaped slider 221 slides along the length of the inclined groove 232 in the inclined groove 232. The baffle 231 is used to limit the position of the T-shaped slider 221 and prevent the T-shaped slider 221 from disengaging from the inclined groove 232.

[0091] Reference Figure 5 Several drive rods 24 are fixedly installed inside the rear mold 3 at positions corresponding to the sliding plate 23. Both ends of the drive rods 24 are fixedly connected to the rear mold 3. The figure describes two drive rods 24 as an example. The drive rods 24 are inclinedly arranged on the sliding plate 23 and penetrate through the sliding plate 23. The sliding plate 23 slides along the axial direction of the drive rods 24.

[0092] Reference Figure 5 When the mold is opened, the drive rod 24 follows the rear mold 3 and moves away from the front mold. During this process, the relative distance between the sliding plate 23 and the front mold remains unchanged. The sliding plate 23 slides in a direction perpendicular to the direction of movement of the rear mold 3. At the same time, the slider slides along the length of the inclined groove 232 to a position away from the front mold, causing the straight ejector 2 to detach from the workpiece.

[0093] Reference Figure 8 , 9 The rear mold 3 has a receiving cavity at the position corresponding to the sliding plate 23. The two opposite side walls of the receiving cavity are slidably connected to the limiting plate 31. The position of the limiting plate 31 relative to the front mold remains unchanged throughout the entire mold opening and closing process. Therefore, it moves relative to the rear mold 3 during the mold opening process. During the mold opening process, the rear mold 3 moves away from the front mold, and the limiting plate 31 slides from the side of the receiving cavity away from the front template to the side closer to the front template.

[0094] Reference Figure 5 , 9 A groove 311 is provided on one side of the two limiting plates 31 that are close to each other along the length direction of the limiting plate 31. The sliding plate 23 is fixed with sliding rods 312 that are adapted to the two side walls of the groove 311. When the sliding plate 23 slides in a direction perpendicular to the rear mold 3 under the drive of the driving rod 24, the sliding rods 312 slide along the length direction of the groove 311, thereby realizing the stable movement of the sliding plate 23.

[0095] Reference Figure 8 , 9 A positioning plate 32 is provided at a position of the rear mold 3 away from the front mold. The positioning plate 32 remains fixed during the mold opening and closing process. Several support rods 321 are fixed at the positions of the positioning plate 32 and the two limiting plates 31. The end of the support rod 321 away from the positioning plate 32 extends towards the front mold and is fixedly connected to the limiting plate 31. The support rod 321 is slidably connected to the rear mold 3.

[0096] The implementation principle of the ejection structure for a mold in Embodiment 2 of this application is as follows:

[0097] When the mold is closed, the rear mold 3 drives the straight ejector 2 (and the inclined ejector 1 on the straight ejector 2) to move closer to the front mold, until the rear mold 3 and the front mold are engaged. An injection cavity is formed between the front mold and the rear mold 3, between the front mold and the straight ejector 2, and between the front mold and the abutment block 11. The through block 111 abuts against the front mold, and the nitrogen spring 15 and the butterfly spring 14 are compressed.

[0098] During the injection molding process, material is poured into the injection cavity to form a workpiece. After the workpiece cools, the following sections are demolded: the part where the rear mold 3 abuts against the workpiece, the part where the ejector 2 abuts against the workpiece, and the part where the abutment block 11 abuts against the workpiece.

[0099] During mold opening, the rear mold 3 moves away from the front mold. During this process, the distance between the limiting plate 31 and the front mold remains constant under the support of the positioning plate 32, and slides relative to the rear mold 3 along the inner wall of the cavity. The drive rod 24 moves the rear mold 3 away from the front mold, and the sliding plate 23 slides in a direction perpendicular to the direction of movement of the rear mold 3. At the same time, the slider slides along the length of the inclined groove 232 and slides away from the front mold in the inclined groove 232, causing the straight ejector 2 to detach from the workpiece.

[0100] Just as the straight ejector 2 is about to detach from the workpiece, the butterfly spring 14 and the nitrogen spring 15 release elastic potential energy together, pushing the inclined ejector 1 to move towards the front mold; the elastic force released instantaneously by the butterfly spring 14 assists the nitrogen spring 15 in pushing the inclined ejector 1 towards the front mold.

[0101] In summary, at the instant the mold opens, the rear mold 3 and the ejector pin 2 move simultaneously away from the front mold. However, in the initial time of mold opening, the rear mold 3 moves faster than the ejector pin 2. Therefore, the rear mold 3 and the ejector pin 2 move relative to each other. The ejector pin 2 is closer to the workpiece than the rear mold 3. When the workpiece adheres to the rear mold 3 in the initial stage of demolding and tends to move under the drive of the rear mold 3, the ejector pin 2 pushes out relative to the rear mold 3 towards the front mold compared to when the mold is closed. Therefore, it is easier to separate the rear mold 3 from the workpiece.

[0102] After the rear mold 3 separates from the workpiece, the straight ejector 2 detaches from the workpiece, and finally, driven by the rear mold 3, the angled ejector 1 detaches from the workpiece. This configuration in Example 2 is suitable for situations where the contact area between the workpiece and the rear mold 3 is large. That is, compared to the undercut 01, the demolding difficulty between the workpiece and the rear mold 3 is greater. Therefore, the straight ejector 2 and the angled ejector 1 first apply a force to the injection mold during demolding, pressing it against the front mold, facilitating the separation of the workpiece from the rear mold 3. Then, the straight ejector 2 and the angled ejector 1 detach from the workpiece sequentially. This segmented detachment facilitates the separation of the workpiece from the rear mold 3.

[0103] Example 3:

[0104] Embodiment 3 of this application discloses an ejection structure for a mold. The difference from Embodiment 2 is that the drive rod 24 of the ejection structure is slidably connected within the rear mold 3. During demolding, the movement direction of the drive rod 24 is the same as the movement direction of the rear mold 3. That is, while the drive rod 24 moves under the influence of the rear mold 3, it also moves away from the front mold relative to the rear mold 3. This ensures that the speed at which the ejector pin 2 moves away from the workpiece is greater than the speed at which the rear mold 3 moves away from the ejector pin 2, causing the ejector pin 2 to detach from the workpiece first, and then the rear mold 3 to detach from the workpiece. This is suitable for situations where the undercut 01 has a complex structure or where the undercut 01 occupies a large proportion of the entire workpiece.

[0105] Reference Figure 10 , 11 The positioning plate 32 is provided with adjustment plates 4 on both sides corresponding to the rear mold 3. The bottom of the adjustment plate 4 is fixed with a sliding block 41. The positioning plate 32 is provided with a sliding groove 42 at the position corresponding to the sliding block 41. The length direction of the sliding groove 42 is set perpendicular to the movement direction of the rear mold 3. The sliding block 41 slides along the length direction of the sliding groove 42, thereby driving the two adjustment plates 4 to move along the surface of the positioning plate 32 towards or away from the rear mold 3.

[0106] Reference Figure 11Each sliding groove 42 on the positioning plate 32 is rotatably connected to a left- or right-hand screw 43. The axial direction of the left- or right-hand screw 43 is set along the length direction of the sliding groove 42. The end of the left- or right-hand screw 43 passes through the sliding block 41 and is threadedly connected to the sliding block 41. Each left- or right-hand screw 43 is provided with a drive motor 44 at both ends of the positioning plate 32. The body of the drive motor 44 is fixedly connected to the end of the positioning plate 32, and the output shaft of the drive motor 44 is fixedly connected to the end of the left- or right-hand screw 43. The rotation of the output shaft of the drive motor 44 drives the left- or right-hand screw 43 to rotate.

[0107] Reference Figure 11 , 12 A drive rack 5 is fixedly connected to one side of the two adjusting plates 4 that are close to each other. The length direction of the drive rack 5 is parallel to the movement direction of the rear mold 3. A drive gear 51 is rotatably connected to the rear mold 3 at the position corresponding to the drive rack 5. When the two adjusting plates 4 move in a direction that brings them closer to each other, the drive rack 5 and the drive gear 51 mesh.

[0108] Reference Figure 13 , 14 A rotating shaft 52 is fixedly connected to the rear mold 3 at the position corresponding to the drive gear 51. The rotating shaft 52 passes through the middle of the drive gear 51 and is rotatably connected to the drive gear 51. A driven wheel 53 is fixedly connected to the side wall of the drive gear 51. The driven wheel 53 is coaxially arranged with the drive gear 51 and rotates synchronously with the drive gear 51 along the rotating shaft 52.

[0109] Reference Figure 13 , 15 A driven rack 54 is fixedly mounted on the rear mold 3 at the end corresponding to the drive rod 24. The length direction of the driven rack 54 is the same as the movement direction of the rear mold 3, and when the driven rack 54 slides along the inner wall of the rear mold 3, its sliding direction is the same as the movement direction of the rear mold 3. A second rotating shaft 55 is fixedly mounted on the rear mold 3 near the driven rack 54. The axis of the second rotating shaft 55 is parallel to that of the first rotating shaft 52. A driven gear 56 is sleeved on the second rotating shaft 55. The driven gear 56 rotates around the outside of the second rotating shaft 55 and meshes with the driven rack 54. A second driven wheel 57 is sleeved on the second rotating shaft 55 and is fixed to the side of the driven gear 56. The driven gear 56 rotates synchronously with the second rotating shaft 55. A belt 58 is tensioned around the first driven wheel 53 and the second driven wheel 57, transmitting the motion from the first driven wheel 53 to the second driven wheel 57 through the belt 58.

[0110] When the drive rack 5 and drive gear 51 mesh, the rear mold 3 drives the drive gear 51 to rotate as it moves away from the front mold. The driven wheel 53 rotates synchronously with the drive gear 51 and transmits the rotation to the driven wheel 57 via the belt 58. The driven wheel 57 drives the driven gear 56 to rotate, which in turn drives the driven rack 54 to move away from the front mold along the rear mold 3. This causes the drive rod 24 to move away from the front mold relative to the rear mold 3 while following the movement of the rear mold 3, so that the speed at which the ejector pin 2 moves away from the workpiece is greater than the speed at which the rear mold 3 moves away from the ejector pin 2. This causes the ejector pin 2 to disengage from the workpiece first, and then the rear mold 3 to disengage from the workpiece.

[0111] Reference Figure 16 On both sides of the rear mold 3 near the adjusting plate 4, there are relief grooves 6 at the positions corresponding to the drive gear 51. The sidewalls of the drive gear 51 extend outward through the relief grooves 6. An adjusting block 61 is provided near the bottom of the relief groove 6. The adjusting block 61 slides along the inner wall of the relief groove 6, and its movement direction is the same as the movement direction of the rear mold 3.

[0112] Reference Figure 11 Additionally, an adjustment assembly 62 is threadedly connected to the left and right rotating lead screw 43. The adjustment assembly 62 includes a connecting rod 621, the length of which is aligned with the movement direction of the rear mold 3. A sliding block 622 is fixedly mounted on the connecting rod 621 near the left and right rotating lead screw 43. The sliding block 622 is threadedly engaged with the left and right rotating lead screw 43. An insertion rod 623 is fixedly mounted on the end of the connecting rod 621 away from the sliding block 622. The length of the insertion rod 623 is perpendicular to the movement direction of the rear mold 3.

[0113] When the left and right screw 43 rotates, causing the adjusting plate 4 to move away from the rear mold 3 and disengage the drive gear 51 and the drive rack 5, the insertion rod 623, driven by the left and right screw 43, inserts into the adjusting block 61 and the relief groove 6, thereby pushing the adjusting block 61 towards the drive gear 51 and engaging it with the drive gear 51, thus preventing the drive gear 51 from rotating during the movement of the rear mold 3. In this mode, the drive rod 24 remains in a constant relative position to the rear mold 3 during the mold opening process.

[0114] The implementation principle of the ejection structure for a mold in Embodiment 3 of this application is as follows:

[0115] Before mass injection molding, sample injection molding can be performed using the two modes described in Example 3 to select the more suitable demolding mode, thereby reducing damage to the injection molded parts during demolding.

[0116] Mode 1: The demolding process is the same as in Example 2, with the demolding sequence as follows: rear mold 3, ejector pin 2, and undercut pin 01. This mode is suitable for injection molding of workpieces where demolding the rear mold 3 is more difficult than demolding the undercut pin 01. During demolding, the drive rod 24 is relatively stationary with respect to the rear mold 3. The ejector pin 2 follows the opening process of the rear mold 3 and moves away from the front mold. The movement speed of the ejector pin 2 is less than that of the rear mold 3. Although the ejector pin 2 follows the rear mold 3 away from the front mold, it pushes out relative to the rear mold 3 towards the workpiece, facilitating demolding of the rear mold 3 first. Furthermore, it can assist the ejection of the angled ejector pin 1, preventing stress concentration and damage to the workpiece caused by only the angled ejector pin 1 pushing out towards the front mold during demolding.

[0117] In this mode, the output shaft of the drive motor 44 rotates, causing the left and right helical screws 43 to rotate. This causes the adjusting plate 4 to move away from the rear mold 3, disengaging the drive gear 51 and the drive rack 5. The insertion rod 623, driven by the left and right helical screws 43, inserts into the adjusting block 61 and the clearance groove 6, pushing the adjusting block 61 towards the drive gear 51. This causes the adjusting block 61 to engage with the drive gear 51, preventing the drive gear 51 from rotating during the movement of the rear mold 3. In this mode, the drive rod 24 and the rear mold 3 remain relatively stationary.

[0118] Mode 2: The demolding sequence is as follows: ejector pin 2, rear mold 3, undercut 01. This mode is suitable for injection molding of workpieces where undercut 01 is more difficult to demold than rear mold 3. Therefore, by making ejector pin 2 follow the movement of rear mold 3, ejector pin 2 moves away from the front mold relative to rear mold 3. The superposition of the two movements makes the speed at which ejector pin 2 moves away from the front mold greater than the speed at which rear mold 3 moves away from the front mold, thus causing ejector pin 2 to detach from the workpiece before rear mold 3. This mode facilitates demolding of workpieces that are difficult to demold at undercut 01 and ensures a certain demolding effect.

[0119] In this mode, the output shaft of the drive motor 44 rotates, which drives the left and right screw 43 to rotate, thereby moving the adjustment plate 4 towards the rear mold 3 so that the drive rack 5 meshes with the drive gear 51. Under the drive of the left and right screw 43, the plug rod 623 disengages from the adjustment block 61 and the relief groove 6.

[0120] When the drive rack 5 and drive gear 51 mesh, the rear mold 3 drives the drive gear 51 to rotate as it moves away from the front mold. The driven wheel 53 rotates synchronously with the drive gear 51 and transmits the rotation to the driven wheel 57 via the belt 58. The driven wheel 57 drives the driven gear 56 to rotate, which in turn drives the driven rack 54 to move away from the front mold along the rear mold 3. This causes the drive rod 24 to move away from the front mold relative to the rear mold 3 while following the movement of the rear mold 3, so that the speed at which the ejector pin 2 moves away from the workpiece is greater than the speed at which the rear mold 3 moves away from the ejector pin 2. This causes the ejector pin 2 to disengage from the workpiece first, and then the rear mold 3 to disengage from the workpiece.

[0121] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An ejection structure for a mold, characterized in that: include: The inclined top (1) slides along the length direction of the guide groove (25) inside the rear mold (3); A butterfly spring (14) is provided in the guide groove (25) and is axially arranged along the length of the guide groove (25); Nitrogen spring (15) is slidably connected inside guide groove (25), and its cylinder end abuts against the side of the butterfly spring (14) away from the bottom wall of guide groove (25). Its piston rod extends along the length of guide groove (25), and its piston rod end is fixed to the bottom of inclined top (1). The sliding plate (23) is slidably connected to the rear mold (3), and the movement direction of the sliding plate (23) is perpendicular to the movement direction of the rear mold (3); The limiting plate (31) is slidably connected inside the rear mold (3), and its position relative to the front mold remains unchanged during the mold opening and closing process. The sliding plate (23) slides on the surface of the limiting plate (31). The positioning plate (32) is set at a position of the rear mold (3) away from the front mold. The positioning plate (32) remains fixed during the mold opening and closing process. The positioning plate (32) is fixedly connected to the limiting plate (31). The adjusting plate (4) is slidably connected to the side of the positioning plate (32) and moves towards or away from the side of the rear mold (3) during movement; The drive rack (5) is fixed on the side of the adjusting plate (4) near the rear mold (3); The drive gear (51) is rotatably connected to the side of the rear mold (3) and meshes with the drive rack (5); Driven wheel 1 (53) is fixed on the side of the drive gear (51) and rotates synchronously with the drive gear (51); Driven rack (54) is fixed to the end of drive rod (24), slides along the inner wall of rear mold (3), and its sliding direction is the same as the movement direction of rear mold (3); Driven gear (56) is rotatably connected in the rear mold (3) and meshes with driven rack (54); Driven wheel 2 (57) is fixed to the side of driven gear (56) and rotates synchronously with driven gear (56); The belt (58) is tensioned outside the driven pulley one (53) and driven pulley two (57).

2. The ejection structure for a mold according to claim 1, characterized in that: include: The protective cover (13) has a cylinder of the nitrogen spring (15) fixed inside the protective cover (13). The piston rod of the nitrogen spring (15) slides along the length of the protective cover (13). The axial direction of the protective cover (13) is set along the length of the guide groove (25). The inclined top (1) is sleeved on the end of the protective cover (13) and slides along the outer wall of the protective cover (13) and along the axial direction of the protective cover (13). The butterfly spring (14) is located at the end of the protective cover (13) away from the inclined top (1), and the protective cover (13) slides along the length direction of the guide groove (25).

3. The ejection structure for a mold according to claim 2, characterized in that: include: Pad 1 (18) is connected to the bottom wall of the protective cover (13). Pad 2 (12) is disposed on the side of pad 1 (18) away from the protective cover (13), and the butterfly spring (14) is disposed between pad 2 (12) and pad 1 (18); The guide post (122) is installed on the second pad (12) with its axial direction along the length of the guide groove (25) and its relative position with the second pad (12) fixed. The bottom of the first pad (18) slides along the axial direction of the guide post (122).

4. The ejection structure for a mold according to claim 3, characterized in that: include: A positioning bolt (121) is connected to the second pad (12), a butterfly spring (14) is sleeved on the outside of the positioning bolt (121), and a guide post (122) is fixed to the end of the positioning bolt (121). The diameter of the positioning bolt (121) is larger than the diameter of the guide post (122).

5. The ejection structure for a mold according to claim 1, characterized in that: include: The straight ejector (2) is slidably connected in the rear mold (3). The guide groove (25) is set inside the straight ejector (2). When the mold is closed, the straight ejector (2) and the front mold form a casting cavity for the workpiece. The drive rod (24) is inclinedly set inside the rear mold (3) and is slidably connected to the sliding plate (23); Inclined groove (232) is provided on sliding plate (23) with an inclined bottom wall; When the rear mold (3) drives the drive rod (24) to move away from the front mold, the sliding plate (23) slides along the rear mold (3), and the straight pusher (2) slides along the length of the inclined groove (232) to a position away from the front mold, causing the straight pusher (2) to detach from the workpiece.

6. The ejection structure for a mold according to claim 1, characterized in that: include: The clearance groove (6) is opened at the position of the drive gear (51) on the rear mold (3); The adjusting block (61) slides along the inner wall of the relief groove (6); When the plug rod (623) slides along the side of the positioning plate (32) and is inserted between the relief groove (6) and the adjusting block (61), the adjusting block (61) and the drive gear (51) engage with each other.

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