Die internal shrinkage structure for forming internal thread of plastic part

Abstract

The utility model relates to the technical field of plastic part forming dies, in particular to a die internal shrinkage structure for forming internal threads of a plastic part, which comprises a base component and a core component, the base component is mounted on an external forming die, the core component is movably connected to the base component, the core component is provided with a wedge-shaped shovel base and a movable insert, and the wedge-shaped shovel base is movably connected with the movable insert. The outer wall of one end of the movable insert is provided with a forming convex strip for forming an internal thread of a plastic part, and the other end of the movable insert is provided with a bottom sliding block which is connected to the base assembly in a sliding manner; and the wedge-shaped shovel base drives the movable insert to translate towards the central axis of the wedge-shaped shovel base by a certain distance, so that the forming convex strip is separated from the internal thread on the inner side wall of the plastic part. In conclusion, forming and demolding of the internal thread of the plastic part can be optimized, the size of the mold can be reduced, the injection molding time can be shortened, and meanwhile the corresponding machining cost can be saved.

Description

Technical Field

[0001] The utility model relates to the technical field of plastic part forming molds, and in particular to a mold retraction structure for forming internal threads of plastic parts. Background Technique

[0002] An injection mold is a tool for producing plastic products. Generally, an injection mold consists of a moving module and a fixed module. A molding cavity and a plastic runner system are formed between the fixed module and the moving module. During injection molding, the moving module and the fixed module are closed, and the mold is clamped on an injection molding machine. At this time, the molten plastic flows into the runner system from the injection port and then into the molding cavity, and cools and forms in the cavity. At the same time, the molten plastic also cools into runner system condensate in the runner system. After the plastic part is formed, the moving module and the fixed module are opened, and the plastic part is ejected from the mold cavity through the ejection system and leaves the mold. When injection molding is required again, the above process can be repeated.

[0003] For some special plastic parts that need to form internal threads, the existing molds generally use traditional gear demolding. However, the traditional gear mold has high processing costs, long molding time, and large space occupation in the mold, so improvements are needed.

[0004] As disclosed in the Chinese patent document with the publication number CN219705945U, an internal thread injection mold for easy demolding is disclosed. The internal thread injection mold for easy demolding includes a moving mold assembly, a fixed mold assembly, and a thread demolding assembly; the moving mold assembly includes a moving mold base and a molding core installed on the moving mold base; the fixed mold assembly includes a fixed mold base, a molding column, and a molding sleeve; the molding column is installed on the fixed mold base, and a molding surface is provided at one end of the molding column close to the moving mold assembly; the molding sleeve is sleeved outside the molding column, and a molding thread is provided on the side wall at one end close to the moving mold assembly, and the other end is threadedly connected to the fixed mold base; the thread demolding assembly includes a power component and a driven gear corresponding to the number of molding sleeves; the driven gear is sleeved outside the molding sleeve and is fixedly connected to the molding sleeve; the power component is installed on the fixed mold base and is used to drive the driven gear to rotate.

[0005] As shown in the attached Figure 1 and attached Figure 6 shown, the size of the traditional gear demolding structure is too large, resulting in too large a space occupied by the overall mold, which is not convenient for reducing the mold volume and decreasing the mold size. Utility Model Content

[0006] The utility model aims to provide a technical solution to solve the above problems in order to overcome the above deficiencies.

[0007] The utility model provides a mold retraction structure for forming internal threads of plastic parts, which includes a base assembly and a core assembly. The base assembly is installed in an external molding mold, and the core assembly is movably connected to the base assembly. The core assembly is provided with a wedge-shaped shovel base and a movable insert. One end outer wall of the movable insert is provided with a forming rib for forming the internal thread of the plastic part, and the other end is provided with a bottom slider. The bottom slider is slidably connected to the base assembly; the wedge-shaped shovel base drives the movable insert to translate a certain distance along the central axis of the wedge-shaped shovel base, so that the forming rib disengages from the internal thread on the inner side wall of the plastic part.

[0008] As a further scheme of the utility model: on the side of the wedge-shaped shovel base facing the movable insert, there is an inclined guide groove, and on the part of the movable insert corresponding to the inclined guide groove, there is an inclined slide rail. The inclined slide rail and the inclined guide groove are mutually engaged to form a sliding connection, and when the wedge-shaped shovel base moves along its central axis, it can drive the movable insert to translate a certain distance perpendicular to the central axis of the wedge-shaped shovel base.

[0009] As a further scheme of the utility model: the movable insert is provided with three arc-shaped blocks and three sector-shaped blocks. The arc-shaped blocks and the sector-shaped blocks cross each other and abut against each other to form a circular concave mold for forming the internal concave space of the plastic part.

[0010] As a further scheme of the utility model: the angle of the inclined angle formed by the inclined slide rail of the sector-shaped block and the central axis of the wedge-shaped shovel base is greater than the angle of the inclined angle formed by the inclined slide rail of the arc-shaped block and the central axis of the wedge-shaped shovel base.

[0011] As a further scheme of the utility model: the base assembly is provided with a retraction fixing plate and a retraction pressing plate. The retraction pressing plate is fixedly connected to the retraction fixing plate, and on the side facing the retraction fixing plate, there is a translation groove adapted to the bottom slider. The bottom slider is slidably connected to the retraction fixing plate and is limited by the translation groove of the retraction pressing plate.

[0012] As a further scheme of the utility model: the translation groove is provided with a first groove and a second groove. The first groove is used to limit the bottom slider of the circular block, and the second groove is used to limit the bottom slider of the sector-shaped block.

[0013] The utility model also provides an injection mold, which is internally provided with the above-mentioned mold retraction structure for forming internal threads of plastic parts, so as to perform injection molding operations on the internal threads of injection products.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. By arranging corresponding core components in the mold retraction structure and utilizing the mutual cooperation between the wedge-shaped shovel base and the movable insert, the wedge-shaped shovel base can drive the movable insert to move inward by a certain distance to form a retracted state, so that the formed convex strip can be separated from the internal thread part of the plastic part, thus completing the overall demolding process. This enables the formation and demolding of the internal thread with a relatively small mold size, and can also shorten the injection molding time and improve production efficiency.

[0016] 2. By using the inclined guide groove of the wedge-shaped shovel base and the inclined slide rail of the movable insert, when the mold is closed or demolded, the wedge-shaped shovel base can move synchronously with the moving module, and then can drive the movable insert to perform corresponding retraction or expansion operations. Thus, the internal thread inside the plastic part can be formed, and at the same time, the demolding operation can be conveniently carried out.

[0017] 3. Three arc-shaped blocks and three sector-shaped blocks are also arranged, and due to the different corresponding inclined angles, the arc-shaped blocks and the sector-shaped blocks can not only be combined to form an integral insert female mold, but also can be retracted separately during demolding, thus completing the demolding operation process.

[0018] Therefore, through the above improvements, the present utility model can provide a mold retraction structure for forming the internal thread of a plastic part, which optimizes the formation and demolding of the internal thread of the plastic part, can not only reduce the size of the mold, but also shorten the injection molding time, and at the same time can save the corresponding processing cost.

[0019] Additional aspects and advantages of the present utility model will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present utility model. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic structural diagram of the base component and the core component of the present utility model;

[0022] Figure 2 It is a schematic structural diagram of the arc-shaped block and the sector-shaped block when the mold is closed in the present utility model;

[0023] Figure 3 It is a schematic structural diagram of the arc-shaped block and the sector-shaped block during the mold opening process in the present utility model;

[0024] Figure 4 It is a structural schematic diagram of the arc-shaped and sector-shaped inserts after mold opening of the present utility model;

[0025] Figure 5 It is a structural schematic diagram of the movable insert of the present utility model;

[0026] Figure 6 It is a cross-sectional schematic diagram of the inclined guide groove of the present utility model;

[0027] Figure 7 It is a cross-sectional schematic diagram of the wedge-shaped shovel base and the movable insert of the present utility model;

[0028] Figure 8 It is a structural schematic diagram of the first groove and the second groove of the present utility model.

[0029] The reference numerals and names in the figure are as follows:

[0030] 10 Base assembly; 11 Retracted fixing plate; 12 Retracted pressure plate; 13 Translation groove; 14 First groove; 15 Second groove; 20 Core assembly; 21 Wedge-shaped shovel base; 22 Inclined guide groove; 30 Movable insert; 31 Forming rib; 32 Bottom slider; 33 Inclined slide rail; 41 Arc-shaped insert; 42 Sector-shaped insert; 50 Plastic part. Detailed implementation manners

[0031] Next, the technical solutions in the embodiments of the present utility model will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0032] Please refer to Figures 1 to 8 , in the embodiment of the present utility model, a mold retraction structure for forming an internal thread of a plastic part includes a base assembly 10 and a core assembly 20. The base assembly 10 is installed in an external molding mold, the core assembly 20 is movably connected to the base assembly 10, the core assembly 20 is provided with a wedge-shaped shovel base 21 and a movable insert 30. One end outer wall of the movable insert 30 is provided with a forming rib 31 for forming the internal thread of the plastic part 50, and the other end thereof is provided with a bottom slider 32. The bottom slider 32 is slidably connected to the base assembly 10; the wedge-shaped shovel base 21 drives the movable insert 30 to translate a certain distance along the central axis of the wedge-shaped shovel base 21, so that the forming rib 31 disengages from the internal thread on the inner side wall of the plastic part 50.

[0033] Specifically, in the field of injection molding dies, corresponding optimization settings are usually made according to the specific structure of the plastic parts to be molded. Due to the particularity of the internal thread, a corresponding hollowing operation needs to be carried out on the inner side wall of the plastic part 50 product, so the traditional mechanism is not convenient to implement. Later, a demolding structure combining a gear and a telescopic cylinder emerged, which enables the formation of the internal thread on the inner side wall of the plastic part 50, and at the same time, the formed thread can be driven to rotate by the gear, so as to withdraw from the part of the internal thread structure. However, due to the relatively complex structure and relatively large size of the gear screw and the telescopic cylinder, the die itself occupies too much space, the molding time is too long, and the processing cost is too high, which is not conducive to energy-saving optimization of production operations.

[0034] Therefore, through research and development, the present utility model proposes a die retraction structure for forming the internal thread of a plastic part. By using the core component 20 provided in the die retraction structure, the wedge-shaped shovel base 21 and the movable insert 30 cooperate with each other, so that the wedge-shaped shovel base 21 can drive the movable insert 30 to move inward a certain distance, forming a retracted state, so that the formed rib 31 can be separated from the internal thread part of the plastic part 50, thus completing the overall demolding process. It can realize the formation and demolding of the internal thread with a relatively small die size, and can also shorten the injection molding time and improve the production efficiency.

[0035] As Figure 5 and Figure 6 shown, preferably, an inclined guide groove 22 is provided on the side of the wedge-shaped shovel base 21 facing the movable insert 30, and an inclined slide rail 33 is provided on the part of the movable insert 30 corresponding to the inclined guide groove 22. The inclined slide rail 33 and the inclined guide groove 22 are engaged with each other to form a sliding connection, and when the wedge-shaped shovel base 21 moves along its central axis, the movable insert 30 can be driven to translate a certain distance perpendicular to the central axis of the wedge-shaped shovel base 21.

[0036] Specifically, by using the inclined guide groove 22 of the wedge-shaped shovel base 21 and the inclined slide rail 33 of the movable insert 30, when the mold is closed or demolded, the wedge-shaped shovel base 21 can move synchronously with the moving module, and then the movable insert 30 can be driven to perform corresponding retraction movement or outward expansion movement. Thus, the internal thread inside the plastic part 50 is formed, and at the same time, the demolding operation can be conveniently carried out. The cooperation between the inclined guide groove 22 and the inclined slide rail 33 can enable the movement of the wedge-shaped shovel base 21 along its axis to drive the corresponding movable insert 30 to move along the radial direction of the wedge-shaped shovel base 21, so as to realize the formation or demolding treatment of the internal thread.

[0037] As Figures 2 to 5As shown, preferably, the movable insert 30 is provided with three arc-shaped segments 41 and three sector-shaped segments 42. The arc-shaped segments 41 and the sector-shaped segments 42 cross each other and abut against each other to form a circular concave die insert for forming the inner concave space of the plastic part 50.

[0038] Specifically, in order to enable the movable insert 30 to not only form a circular concave die insert for forming the internal thread but also move inwards to complete the demolding operation, the movable insert 30 can be set as three arc-shaped segments 41 of the same size and three sector-shaped segments 42 of the same size. The arc part of the arc-shaped segment 41 faces the outside of the movable insert 30, thus forming the outer side wall of the movable insert 30. At the same time, the short side part of the sector-shaped segment 42 also faces the outside of the movable insert 30 and has a certain bending amplitude, thus forming the outer side wall of the movable insert 30.

[0039] Secondly, corresponding forming ribs 31 are provided on the parts where the arc-shaped segments 41 and the sector-shaped segments 42 form the outer side wall of the movable insert 30, and all the forming ribs 31 can be combined to form an integral rib for forming the internal thread of the plastic part 50.

[0040] Thirdly, the long side part of the sector-shaped segment 42 faces the inside of the movable insert 30. At the same time, the inclined slide rail 33 is also provided on the long side part of the sector-shaped segment 42, enabling it to move towards the inside of the movable insert 30 under the drive of the inclined guide groove 22. Similarly, the part of the arc-shaped segment 41 facing the inside of the movable insert 30 is also provided with a corresponding inclined slide rail 33, enabling it to move towards the inside of the movable insert 30 under the drive of the inclined guide groove 22. Thus, the demolding operation of the internal thread of the plastic part 50 is realized.

[0041] As Figure 6 and Figure 7 shown, preferably, the angle of the inclined angle formed by the inclined slide rail 33 of the sector-shaped segment 42 and the central axis of the wedge-shaped shovel base 21 is greater than the angle of the inclined angle formed by the inclined slide rail 33 of the arc-shaped segment 41 and the central axis of the wedge-shaped shovel base 21.

[0042] Specifically, during mold opening, that is, when the wedge-shaped shovel base 21 moves away from the plastic part 50, it can first drive the sector-shaped segment 42 to translate a certain distance towards the central axis of the wedge-shaped shovel base 21, thus creating a certain space for the arc-shaped segment 41, enabling the arc-shaped segment 41 to then also translate a certain distance towards the central axis of the wedge-shaped shovel base 21, and further enabling the movable insert 30 to disengage from the inner side wall of the plastic part 50 for the demolding operation. At the same time, it can also enable the forming ribs 31 on the movable insert 30 to disengage from the internal thread on the inner side wall of the plastic part 50, thus completing the operation of the mold shrinking inwards.

[0043] Secondly, contrary to the above operation, when the mold is closed, that is, when the wedge-shaped shovel base 21 moves in the direction approaching the plastic part 50, it can drive the arc-shaped segment 41 to abut against the inner side wall of the plastic part 50 first. Subsequently, the sector segment 42 is further translated a certain distance towards the inner side wall of the plastic part 50 and abuts against the inner side wall of the plastic part 50, so that the sector segment 42 and the arc-shaped segment 41 abut against each other to form a cylindrical integral movable insert 30, and the inner cavity of the plastic part 50 is formed. At the same time, the forming ribs 31 provided thereon can also form the internal thread on the inner wall of the plastic part 50.

[0044] As Figures 5 to 7 shown, preferably, the base assembly 10 is provided with a retractable fixing plate 11 and a retractable pressing plate 12. The retractable pressing plate 12 is fixedly connected to the retractable fixing plate 11, and a translation groove 13 adapted to the bottom slider 32 is provided on the side facing the retractable fixing plate 11. The bottom slider 32 is slidably connected to the retractable fixing plate 11 and is limited by the translation groove 13 of the retractable pressing plate 12.

[0045] Specifically, in order to make the translation direction of the movable insert 30 more accurate, corresponding translation grooves 13 can also be provided at corresponding positions of the retractable pressing plate 12, so that the movable insert 30 can only perform parallel movement within the translation grooves 13.

[0046] As Figure 8 shown, preferably, the translation groove 13 is provided with a first groove 14 and a second groove 15. The first groove 14 is used to limit the bottom slider 32 of the arc-shaped segment 41, and the second groove 15 is used to limit the bottom slider 32 of the sector segment 42.

[0047] Specifically, in order to guide the movement of the movable insert 30, the first groove 14 and the second groove 15 can be set according to the size of the bottom slider 32. Since the bottom slider 32 of the sector segment 42 is relatively small, a relatively small second groove 15 can be set. Similarly, since the bottom slider 32 of the arc-shaped segment 41 is relatively large, a relatively large first groove 14 can be set.

[0048] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. An inner contraction structure of a mold for forming an internal thread of a molded plastic part, characterized in that, It includes a base assembly (10) and a core assembly (20). The base assembly (10) is installed on an external molding die, and the core assembly (20) is movably connected to the base assembly (10). The core assembly (20) is provided with a wedge-shaped shovel base (21) and a movable insert (30). One end outer wall of the movable insert (30) is provided with a molding rib (31) for molding the internal thread of the molded plastic part (50), and the other end is provided with a bottom slider (32). The bottom slider (32) is slidably connected to the base assembly (10); the wedge-shaped shovel base (21) drives the movable insert (30) to translate a certain distance along the central axis of the wedge-shaped shovel base (21), so that the molding rib (31) disengages from the internal thread on the inner side wall of the plastic part (50).

2. The mold retraction structure for forming an internal thread of a molded plastic part according to claim 1, characterized in that, One side of the wedge-shaped shovel base (21) facing the movable insert (30) is provided with an inclined guide groove (22), and a corresponding part of the movable insert (30) to the inclined guide groove (22) is provided with an inclined slide rail (33). The inclined slide rail (33) and the inclined guide groove (22) are engaged with each other to form a sliding connection, and when the wedge-shaped shovel base (21) moves along its central axis, it can drive the movable insert (30) to translate a certain distance perpendicular to the central axis of the wedge-shaped shovel base (21).

3. The mold retraction structure for forming an internal thread of a molded plastic part according to claim 2, characterized in that, The movable insert (30) is provided with three arc-shaped blocks (41) and three sector-shaped blocks (42). The arc-shaped blocks (41) and the sector-shaped blocks (42) cross each other and abut against each other to form a circular concave die for molding the internal concave space of the plastic part (50).

4. The mold retraction structure for forming internal threads of a molded plastic part according to claim 3, wherein, The angle of the inclined angle formed by the inclined slide rail (33) of the sector-shaped block (42) and the central axis of the wedge-shaped shovel base (21) is greater than the angle of the inclined angle formed by the inclined slide rail (33) of the arc-shaped block (41) and the central axis of the wedge-shaped shovel base (21).

5. The mold retraction structure for forming an internal thread of a molded plastic part according to claim 1, characterized in that, The base assembly (10) is provided with a retractable fixing plate (11) and a retractable pressing plate (12). The retractable pressing plate (12) is fixedly connected to the retractable fixing plate (11), and a translation groove (13) adapted to the bottom slider (32) is provided on the side facing the retractable fixing plate (11). The bottom slider (32) is slidably connected to the retractable fixing plate (11) and is limited by the translation groove (13) of the retractable pressing plate (12).

6. The mold retraction structure for forming an internal thread of a molded plastic part according to claim 5, characterized in that, The translation groove (13) is provided with a first groove (14) and a second groove (15). The first groove (14) is used to limit the bottom slider (32) of the circular block, and the second groove (15) is used to limit the bottom slider (32) of the sector-shaped block (42).

7. An injection mold, characterized in that, It internally has an internal retraction structure of a mold for molding the internal thread of a plastic part as described in any one of claims 1-6, so as to perform an injection molding operation on the internal thread of an injection molded product.

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