Injection mold inner shrink mechanism

Abstract

The utility model provides a kind of injection mould inner shrink mechanism, including the slider mechanism and inner shrink mechanism being connected with each other, slider mechanism drives inner shrink mechanism first radial inner shrink again axial movement.Inner shrink mechanism includes the end cap being connected with slider mechanism.Cone-shaped inner shrink shaft is equipped with along end cap axial, and inner shrink shaft is driven connection by inner shrink cover and slider mechanism.Transmission connection.The end cap and inner shrink shaft between are equipped with a inner shrink insert group, and inner shrink insert group inboard wall is adapted with the outside wall of inner shrink shaft.Inner shrink shaft outside wall is equipped with the sliding slot being set around its axis array.Inner shrink insert group inboard wall is equipped with the sliding ridge being adapted with sliding slot.When inner shrink shaft is axially moved relative to inner shrink insert group, inner shrink shaft drives inner shrink insert group radial contraction.The utility model realizes first radial inner shrink again axial movement demolding action, effectively avoids the direct scraping of traditional inner shrink mechanism with product reverse buckling portion during demolding process, and improves the quality of injection molding product.

Description

Technical Field

[0001] This utility model belongs to the field of injection mold technology, and specifically relates to an injection mold internal retraction mechanism. Background Technology

[0002] In injection molding, for products with undercuts, molds typically require specialized side-pulling mechanisms or inward-shrinking sliding mechanisms. Inward-shrinking sliding mechanisms usually use the linear motion of a slider to drive one or more sets of inserts to retract radially, thus achieving undercut demolding. However, existing inward-shrinking mechanisms still pose a risk of scratching the product during the shrinkage process. Furthermore, the driving and locking mechanisms of some existing inward-shrinking mechanisms are not adequately designed, causing them to easily retract or shift under high injection pressure, affecting product dimensional accuracy, and resulting in rapid wear and a short service life.

[0003] Therefore, the above problems urgently need to be solved. Utility Model Content

[0004] Purpose of the utility model: In order to overcome the above shortcomings, this utility model provides an injection mold inward shrinkage mechanism, which realizes a compound core-pulling action of first radially shrinking and then axially moving, effectively avoiding direct scraping between the traditional inward shrinkage mechanism and the undercut part of the product during the demolding process, and improving the quality of injection molded products.

[0005] Technical Solution: To achieve the above objectives, this utility model provides an injection mold retraction mechanism, including a slider mechanism and a retraction mechanism connected to each other. The slider mechanism drives the retraction mechanism to retract radially and then move axially. The retraction mechanism includes an end cap connected to the slider mechanism. A conical retraction shaft is provided along the axial direction of the end cap, and the retraction shaft is connected to the slider mechanism via a retraction sleeve. An retraction insert assembly is provided between the end cap and the retraction shaft, and the inner sidewall of the retraction insert assembly is adapted to the outer sidewall of the retraction shaft. The outer sidewall of the retraction shaft is provided with grooves arranged in an array around its axis. The inner sidewall of the retraction insert assembly is provided with sliding ridges adapted to the grooves. When the retraction shaft moves axially relative to the retraction insert assembly, the retraction shaft drives the retraction insert assembly to retract radially. When the mold is being separated, the slider mechanism is activated, and the inner shrink shaft is displaced axially. The groove on its conical outer wall cooperates with the sliding edge on the inner side of the inner shrink insert assembly, converting the axial movement into the radial shrinking movement of the inner shrink insert assembly. Subsequently, the slider mechanism drives the entire inner shrink mechanism to move axially, completing the demolding action.

[0006] This invention utilizes a slider mechanism to drive an internal shrinkage mechanism, achieving a compound action of radial shrinkage followed by axial movement. This effectively avoids direct scraping between the traditional internal shrinkage mechanism and the undercut area of ​​the product during demolding, thus improving the quality of the injection molded product. The tapered internal shrinkage shaft, combined with a sliding groove and sliding edge, ensures a smooth and precise radial shrinkage process, preventing jamming.

[0007] Furthermore, in the aforementioned injection mold shrinkage mechanism, the shrinkage sleeve has a through cavity along its axis, and a limiting protrusion is provided on the inner sidewall of the through cavity. The limiting protrusion is connected to the shrinkage shaft on the side away from the slider mechanism. A pull stud is slidably connected inside the through cavity, with the head of the pull stud located on the side of the limiting protrusion near the slider mechanism, and the tail of the pull stud extending into a through hole along the axis of the shrinkage shaft. A pressure block is provided on the side of the shrinkage insert assembly away from the slider mechanism, and the pressure block is connected to the pull stud. When the pressure block and the shrinkage insert assembly abut, a gap remains between the pull stud head and the limiting protrusion. Before mold parting, the pull stud head and the limiting protrusion maintain a distance. During mold parting, the slider mechanism first drives the inner shrink shaft to generate axial displacement, causing the inner shrink insert assembly to shrink radially. Then, the limiting protrusion on the inner shrink sleeve abuts against the head of the pull stud. The limiting protrusion pulls the pull stud back, which in turn pulls the pressure block back. At this point, the inner shrink insert assembly shrinks radially into the end cap. The end cap retracts and abuts against the end cap, achieving end cap demolding. The slider mechanism further retracts, pulling the end cap and pressure block out of the mold cavity as a whole, completing demolding and achieving stepped demolding, effectively avoiding scratching between the insert and the product. This mechanism, through the gap design between the pull stud and the limiting protrusion, ensures that the inner shrink insert assembly shrinks radially first to detach from the product undercut, and then is axially pulled out as a whole, ensuring demolding safety. The through-cavity structure of the inner shrink sleeve provides a stable sliding guide for the pull stud, ensuring demolding stability.

[0008] Furthermore, in the aforementioned injection mold retraction mechanism, the pull pin head is connected to a locking block, with both ends of the locking block protruding from through slots provided on both sides of the retraction sleeve. The end cap locks the locking block within a groove provided in the slider mechanism. A groove is provided on the connecting surface between the slider mechanism and the end cap. When the end cap and slider mechanism are connected, the end cap causes the locking block within the groove of the slider mechanism to move synchronously with the end cap. In the mold-closed state, the locking block locks the pull pin, preventing the pull pin from moving and thus affecting the stability of the pressure block, thereby improving product quality.

[0009] Furthermore, in the aforementioned injection mold retraction mechanism, the retraction insert group includes a set of large sliding inserts and a set of small sliding inserts, with the large and small sliding inserts alternately arranged. The sliding edge includes a large sliding edge and a small sliding edge, with the large sliding edge located inside the large sliding insert and the small sliding edge located inside the small sliding insert.

[0010] Furthermore, in the aforementioned injection mold shrinkage mechanism, the inclination angle of the inner side of the small sliding edge is set to be greater than that of the inner side of the large sliding edge. This angle difference allows the small sliding insert to generate a larger radial shrinkage displacement when the axial displacement is the same distance, thus avoiding interference between the small and large sliding edges.

[0011] Furthermore, in the aforementioned injection mold shrinkage mechanism, the outer wall of the small sliding insert is provided with a limiting groove extending along the small sliding edge. The inner side of the end cap is provided with a limiting protrusion that matches the limiting groove. The limiting protrusion on the inner side of the end cap slides in conjunction with the limiting groove on the outer wall of the small sliding insert, effectively preventing the small sliding insert from circumferentially deflecting during radial shrinkage.

[0012] Furthermore, in the aforementioned injection mold retraction mechanism, an insert is provided on the side of the end cap away from the slider mechanism, the retraction insert assembly is fitted inside the insert, and the pressure block is located on the side of the retraction insert assembly away from the insert. The insert, the retraction insert assembly, and the pressure block together constitute the undercut insert that forms the product undercut.

[0013] Furthermore, in the aforementioned injection mold shrinkage mechanism, the slider mechanism includes an outer slider, an inner slider, a slanted guide post, and a locking block. The outer slider is connected to the end cap, and the inner slider is connected to the inner shrinkage sleeve. The inner slider is slidably connected to the inner side of the outer slider, and the slanted guide post is slidably connected to the slanted hole provided in the inner slider. The locking block is located on the side of the outer slider away from the end cap. During mold closing, the locking block abuts against the outer slider and the inner slider respectively through the slanted surface. During mold parting, the slanted guide post drives the inner slider to move axially, causing the inner shrinkage sleeve and the inner shrinkage shaft to retract, causing the inner shrinkage insert assembly to shrink radially. Subsequently, the limiting protrusion ring provided in the inner shrinkage sleeve drives the pull stud to retract, the pull stud pulls the pressure block to retract, and at the same time, the locking block drives the end cap and the outer slider to retract and be withdrawn as a whole.

[0014] During the mold closing stage, the inclined guide pillar drives the inner and outer sliders to move into the mold cavity. The inner slider drives the inner shrinking axis to move into the end cap, causing the inner shrinking insert assembly to expand radially. At the same time, the outer slider pushes the pull stud to move into the mold cavity through the locking block, causing the inner shrinking insert assembly and the end cap to reset forward. This allows the insert of the end cap, the inner shrinking insert assembly, and the pressure block to assemble, forming the undercut insert of the molded product.

[0015] Furthermore, in the aforementioned injection mold retraction mechanism, wear-resistant blocks are provided at the contact points between the locking block and the outer and inner sliders. These wear-resistant blocks reduce frictional wear between the locking block and the outer and inner sliders, extending the service life of the mechanism.

[0016] As can be seen from the above technical solution, this utility model has the following beneficial effects: ①The internal shrinkage mechanism of the injection mold of this utility model adopts a two-stage demolding design. First, the internal shrinkage insert group is driven to shrink radially and detach from the product undercut. Then, the gap between the pull stud and the limiting protrusion ring delays the triggering of the overall axial withdrawal, completely avoiding the risk of scratching between the insert and the product surface.

[0017] ② The embedded fit between the locking block and the groove of the slider mechanism effectively fixes the position of the pull stud in the mold closing state, preventing the pressure block from shifting due to high injection pressure and ensuring the stability of the undercut molding dimensions.

[0018] ③ The large and small sliding inserts adopt a differentiated sliding edge tilt angle design, which, together with the limiting protrusion of the end cover and the limiting sliding groove guide structure of the small sliding insert, avoids the shrinkage interference of irregular inserts and eliminates the circumferential wobble during radial movement, thereby improving the motion accuracy of the mechanism. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the internal retraction mechanism of the injection mold of this utility model; Figure 2 This is an axial sectional view of the injection mold retraction mechanism of this utility model; Figure 3 An exploded view of the retraction mechanism; Figure 4 This is a schematic diagram of the structure of the recessed insert assembly; Figure 5 This is a schematic diagram of the structure of the inward-shrinking shaft; Figure 6 This is a schematic diagram of the inner sleeve structure; Figure 7 This is a schematic diagram of the structure of the inner shrink shaft and inner shrink sleeve in the mold-closed state; Figure 8 This is an exploded view of the recessed insert assembly shown. Figure 9 This is a side view of the small row insert; Figure 10 This is a side view of the large row insert; Figure 11 This is a schematic diagram of the end cap structure; Figure 12 This is an exploded view of the slider mechanism.

[0020] In the diagram: 1. Slider mechanism, 11. Outer slider, 12. Inner slider, 13. Inclined guide post, 14. Locking block, 15. Wear-resistant block, 2. Inner retraction mechanism, 21. End cap, 211. Limiting protrusion, 212. Inlay, 22. Inner retraction insert assembly, 221. Sliding edge, 2211. Large sliding edge, 2212. Small sliding edge, 222. Large sliding insert, 223. Small sliding insert, 2233. Limiting groove, 23. Inner retraction shaft, 231. Groove, 24. Inner retraction sleeve, 241. Through cavity, 242. Limiting protrusion ring, 25. Pull stud, 26. Locking block, 27. Pressure block. Detailed Implementation

[0021] Example 1 like Figure 1-5The diagram illustrates an injection mold retraction mechanism, comprising a slider mechanism 1 and a retraction mechanism 2 interconnected. The slider mechanism 1 drives the retraction mechanism 2 to retract radially and then move axially. The retraction mechanism 2 includes an end cap 21 connected to the slider mechanism 1. A conical retraction shaft 23 is provided along the axial direction of the end cap 21, and the retraction shaft 23 is connected to the slider mechanism 1 via a retraction sleeve 24. An retraction insert assembly 22 is provided between the end cap 21 and the retraction shaft 23, and the inner sidewall of the retraction insert assembly 22 is adapted to the outer sidewall of the retraction shaft 23. The outer sidewall of the retraction shaft 23 is provided with grooves 231 arranged in an array around its axis (see...). Figure 5 The inner wall of the inner recessed insert assembly 22 is provided with a sliding rib 221 that matches the sliding groove 231. When the inner recessed shaft 23 moves axially relative to the inner recessed insert assembly 22, the inner recessed shaft 23 drives the inner recessed insert assembly 22 to retract radially.

[0022] like Figure 2-6 The injection mold shrinking mechanism shown has an inner shrinking sleeve 24 with a through cavity 241 along its axis. A limiting protrusion 242 is provided on the inner wall of the through cavity 241. The limiting protrusion 242 is connected to the inner shrinking shaft 23 on the side away from the slider mechanism 1. A pull stud 25 is slidably connected within the through cavity 241. The head of the pull stud 25 is located on the side of the limiting protrusion 242 near the slider mechanism 1, and the tail of the pull stud 25 extends into a through hole along the axis of the inner shrinking shaft 23. A pressure block 27 is provided on the side of the inner shrinking insert assembly 22 away from the slider mechanism 1, and the pressure block 27 is connected to the pull stud 25. When the pressure block 27 and the inner shrinking insert assembly 22 abut, a gap remains between the head of the pull stud 25 and the limiting protrusion 242. Before mold parting, the head of the pull stud 25 and the limiting protrusion 242 maintain a distance.

[0023] In this embodiment, the head of the pull pin 25 is connected to a locking block 26. The two ends of the locking block 26 pass through the through grooves provided on both sides of the inner sleeve 24, and the end cap 21 locks the locking block 26 in the groove provided in the slider mechanism 1.

[0024] like Figure 7-10 The shown injection mold retraction mechanism includes a retraction insert group 22 comprising a set of large sliding inserts 222 and a set of small sliding inserts 223, which are alternately arranged. The sliding rib 221 includes a large sliding rib 2211 and a small sliding rib 2212, with the large sliding rib 2211 located inside the large sliding insert 222 and the small sliding rib 2212 located inside the small sliding insert 223.

[0025] In this embodiment, the inclination angle of the inner side of the small sliding ridge 2212 is set to be greater than the inclination angle of the inner side of the large sliding ridge 2211. This angle difference causes the small sliding insert 223 to produce a larger radial contraction displacement when the axial displacement is the same distance, thus avoiding interference between the small sliding ridge 2212 and the large sliding ridge 2211.

[0026] like Figure 8 , 11 The injection mold shrinkage mechanism shown has a limiting groove 2233 extending along the small sliding edge 2212 on the outer wall of the small sliding insert 223. The inner side of the end cap 21 has a limiting protrusion 211 that matches the limiting groove 2233. The limiting protrusion 211 on the inner side of the end cap 21 slides in conjunction with the limiting groove 2233 on the outer wall of the small sliding insert 223, effectively preventing circumferential deflection of the small sliding insert 223 during radial shrinkage.

[0027] In this embodiment, the end cap 21 has an insert 212 on the side away from the slider mechanism 1, the inner recessed insert group 22 is sleeved inside the insert 212, and the pressure block 27 is located on the side of the inner recessed insert group 22 away from the insert 212. The insert 212, the inner recessed insert group 22 and the pressure block 27 together constitute an undercut insert that forms the undercut of the product.

[0028] like Figure 12 The injection mold retraction mechanism shown includes an outer slider 11, an inner slider 12, an inclined guide post 13, and a locking block 14. The outer slider 11 is connected to the end cap 21, and the inner slider 12 is connected to the inner retraction sleeve 24. The inner slider 12 is slidably connected to the inner side of the outer slider 11, and the inclined guide post 13 is slidably connected to the inclined hole provided in the inner slider 12. The locking block 14 is located on the side of the outer slider 11 away from the end cap 21. During mold closing, the locking block 14 abuts against the outer slider 11 and the inner slider 12 through the inclined surfaces.

[0029] In this embodiment, a wear-resistant block 15 is provided at the contact point between the locking block 14 and the outer slider 11 and the inner slider 12. The wear-resistant block 15 can reduce the frictional wear between the locking block 14 and the outer slider 11 and the inner slider 12, and extend the service life of the mechanism.

[0030] The workflow of this utility model includes the following steps: During the mold parting stage: The inclined guide post 13 drives the inner slider 12 to move axially, causing the inner shrink sleeve 24 and the inner shrink shaft 23 to retract. The groove 231 of the inner shrink shaft 23 engages with the sliding edge 221 of the inner shrink insert assembly 22, driving the inner shrink insert assembly 22 to radially shrink and disengage from the product undercut. Subsequently, the limiting protrusion 242 of the inner shrink sleeve 24 abuts against the head of the pull stud 25, causing the pull stud 25 to retract. The pull stud 25 pulls the pressure block 27 back, and at the same time, the pull stud 25 drives the end cap 21 and the outer slider 11 to be axially withdrawn from the mold cavity through the locking block 26, completing the demolding action.

[0031] During the mold closing stage: The inclined guide post 13 drives the inner slider 12 and the outer slider 11 to move into the mold cavity. The inner slider 12 pushes the inner shrink shaft 23 to move towards the end cover 21, causing the inner shrink insert assembly 22 to expand radially; at the same time, the outer slider 11 pushes the pull stud 25 to move towards the end cover 21 through the locking block 26, until the end cover 21, the insert 212, and the inner shrink insert assembly 22 are joined together to form the undercut insert of the molded product. The inclined surface of the locking block 14 abuts against the outer slider 11 and the inner slider 12 respectively, locking the outer slider 11 and the inner slider 12.

[0032] The above embodiments are exemplary and are intended to illustrate the technical concept and features of this utility model, so that those skilled in the art can understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be covered within the scope of protection of this utility model.

Claims

1. A retraction mechanism for an injection mold, characterized in that: The device includes a slider mechanism (1) and an inward retraction mechanism (2) connected to each other. The slider mechanism (1) drives the inward retraction mechanism (2) to retract radially and then move axially. The inward retraction mechanism (2) includes an end cap (21) connected to the slider mechanism (1). A conical inward retraction shaft (23) is provided along the axial direction of the end cap (21). The inward retraction shaft (23) is connected to the slider mechanism (1) via an inward retraction sleeve (24). An inward retraction space is provided between the end cap (21) and the inward retraction shaft (23). The insert assembly (22) has an inner wall that is adapted to the outer wall of the inner shaft (23); the outer wall of the inner shaft (23) is provided with a groove (231) arranged in an array around its axis; the inner wall of the insert assembly (22) is provided with a sliding ridge (221) adapted to the groove (231); when the inner shaft (23) moves axially relative to the insert assembly (22), the inner shaft (23) drives the insert assembly (22) to retract radially.

2. The injection mold retraction mechanism according to claim 1, characterized in that: The inner sleeve (24) has a through cavity (241) along the axis, and the inner wall of the through cavity (241) has a limiting protrusion ring (242); the limiting protrusion ring (242) is connected to the inner shaft (23) on the side away from the slider mechanism (1); a pull stud (25) is slidably connected in the through cavity (241), the head of the pull stud (25) is located on the side of the limiting protrusion ring (242) near the slider mechanism (1), and the tail end of the pull stud (25) extends into the through hole provided along the axis of the inner shaft (23); the inner insert assembly (22) has a pressure block (27) on the side away from the slider mechanism (1), and the pressure block (27) is connected to the pull stud (25); when the pressure block (27) and the inner insert assembly (22) abut, there is a gap between the head of the pull stud (25) and the limiting protrusion ring (242).

3. The injection mold retraction mechanism according to claim 2, characterized in that: The head of the pull stud (25) is connected to a locking block (26), and the two ends of the locking block (26) pass through the through grooves provided on both sides of the inner sleeve (24); the end cap (21) locks the locking block (26) in the groove provided in the slider mechanism (1).

4. The injection mold retraction mechanism according to claim 1, characterized in that: The inner recessed insert group (22) includes a set of large row inserts (222) and a set of small row inserts (223), the large row inserts (222) and the small row inserts (223) are alternately arranged; the sliding edge (221) includes a large sliding edge (2211) and a small sliding edge (2212), the large sliding edge (2211) is located inside the large row insert (222), and the small sliding edge (2212) is located inside the small row insert (223).

5. The injection mold retraction mechanism according to claim 4, characterized in that: The inclination angle of the inner side of the small sliding edge (2212) is set to be greater than the inclination angle of the inner side of the large sliding edge (2211).

6. The injection mold retraction mechanism according to claim 4, characterized in that: The outer wall of the small sliding insert (223) is provided with a limiting groove (2233) extending along the small sliding edge (2212); the inner side of the end cap (21) is provided with a limiting protrusion (211) that matches the limiting groove (2233).

7. The injection mold retraction mechanism according to claim 2, characterized in that: The end cap (21) is provided with an insert (212) on the side away from the slider mechanism (1), the inner recess insert group (22) is sleeved on the inner side of the insert (212), and the pressure block (27) is provided on the side of the inner recess insert group (22) away from the insert (212); the insert (212), the inner recess insert group (22) and the pressure block (27) together constitute an undercut insert that forms the product undercut.

8. The injection mold retraction mechanism according to claim 1, characterized in that: The slider mechanism (1) includes an outer slider (11), an inner slider (12), an inclined guide post (13), and a locking block (14); the outer slider (11) is connected to the end cap (21), the inner slider (12) is connected to the inner sleeve (24), the inner slider (12) is slidably connected to the inner side of the outer slider (11), and the inclined guide post (13) is slidably connected to the inclined hole provided in the inner slider (12); the locking block (14) is located on the side of the outer slider (11) away from the end cap (21); when the mold is closed, the locking block (14) abuts against the outer slider (11) and the inner slider (12) respectively through the inclined surface.

9. The injection mold retraction mechanism according to claim 8, characterized in that: Wear-resistant blocks (15) are provided at the contact points between the locking block (14) and the outer slider (11) and the inner slider (12).

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