A slanted core pulling structure on a straight top of a two-color injection mold

By linking the direct ejector assembly and the angled core-pulling assembly, the problems of high cost, long processing time and low assembly efficiency in traditional two-color mold structures are solved, achieving efficient demolding and improved wear resistance, making it suitable for mold applications in multiple scenarios.

CN224374754UActive Publication Date: 2026-06-19NINGBO KEXIN MOLD CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
NINGBO KEXIN MOLD CO LTD
Filing Date
2025-07-10
Publication Date
2026-06-19

AI Technical Summary

⚠Technical Problem

Traditional two-color molds with slanted core-pulling structures suffer from high mold costs, long processing times, and low assembly efficiency. In particular, the hydraulic cylinder-driven slider structure requires additional space, increases material costs, leads to a high failure rate, and results in excessively long processing times.

⚗Method used

The design employs a linkage between the straight-push assembly and the angled core-pulling assembly. Efficient demolding is achieved through the composite motion track of the angled guide groove and the core-pulling assembly. The pull hook, made of high-hardness material, is mechanically interlocked with the core-pulling base for forced traction. Combined with a spring-assisted system, a limit rod, and a floating guide system, the stability and accuracy of the core-pulling stroke are ensured.

🎯Benefits of technology

It achieves efficient demolding of complex undercuts, reduces processing time and debugging cycle, improves the wear resistance and rigidity of the mold, reduces friction loss, and improves assembly efficiency and overall mold life.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model belongs to mould technical field especially is a kind of oblique core-pulling structure on direct top of two-color injection mould. Including core-pulling mechanism, core-pulling mechanism includes direct top subassembly and is arranged in the oblique core-pulling subassembly of direct top subassembly inside;Direct top subassembly includes direct top block.The utility model through the linkage design of direct top subassembly and oblique core-pulling subassembly has realized the efficient stripping of complex reverse buckle, and oblique guide slot composite track makes core-pulling gradient and product stripping angle accurate matching and increases safety margin, ensure that core-pulling stroke stability, the hook made of high hardness material is forced to pull with core-pulling base by mechanical interlocking structure, and wear resistance and rigidity significantly improve, while self-lubricating mating surface reduces friction loss, spring auxiliary system thrust is optimized and matched with core-pulling weight, both guarantee thorough stripping and prevent overload, limiting rod and floating guide system accurate control stroke range, overall structure is simple, compact and has high debugging efficiency, with wide application prospect.
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Description

Technical Field

[0001] This utility model relates to the field of mold technology, specifically to a slanted core-pulling structure on the straight top of a two-color injection mold. Background Technology

[0002] Molds are various shapes and tools used in industrial production to obtain desired products through methods such as injection molding, blow molding, extrusion, die casting, forging, smelting, and stamping. In short, a mold is a tool used to create shaped objects. This tool is composed of various parts, and different molds are composed of different parts. It mainly achieves the processing of the object's shape by changing the physical state of the material being molded. Often called the "mother of industry," two-color molds are used when two plastic materials are injected onto the same injection molding machine, forming the product in two stages, but the product only exits the mold once. This molding process is generally called two-material injection molding, usually completed with one set of molds, and requires a specialized two-color injection molding machine.

[0003] As the two-color mold industry develops towards higher precision and higher efficiency, the limitations of traditional inclined core-pulling structures are becoming increasingly apparent; in existing technologies, the structure of a hydraulic cylinder-driven slider has obvious defects:

[0004] First, the installation of the hydraulic cylinder requires additional space, which increases the thickness of the template by 20-30mm, reducing both strength and material costs.

[0005] Secondly, the failure rate of the hydraulic system accounts for 35% of the total mold failures, and the repair time is as long as 4-8 hours per instance. More seriously, traditional structure processing requires multiple workpiece flipping, and the CNC machining time is 15-20 hours longer than that of conventional structure. For example, actual test data of a certain automotive parts mold shows that the mold using traditional inclined core pulling has an average of 8 trial moldings and a debugging cycle of up to 7 days, which seriously affects the processing efficiency.

[0006] Therefore, we propose a slanted core-pulling structure on the straight top of a two-color injection mold to solve the above problems. Utility Model Content

[0007] (a) Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this utility model provides a slanted core-pulling structure on the straight top of a two-color injection mold, which solves the problems of high cost, long processing time, and low assembly efficiency of traditional molds mentioned in the background.

[0009] (II) Technical Solution

[0010] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0011] A slanted core-pulling structure on a straight ejector of a two-color injection mold includes a core-pulling mechanism, wherein the core-pulling mechanism includes a straight ejector assembly and a slanted core-pulling assembly disposed inside the straight ejector assembly;

[0012] The direct-acting component includes a direct-acting block, and the interior of the direct-acting block is provided with an inclined guide groove;

[0013] The inclined core-pulling assembly includes a core-pulling body and a hook. The core-pulling body is fitted inside the inclined guide groove. A core-pulling base is provided at one end of the inclined guide groove, and one end of the core-pulling base is connected to one end of the hook.

[0014] Furthermore, the inside of the straight top block is provided with spring grooves located on both sides of the inclined guide groove, and the inclined core-pulling assembly also includes a spring disposed in the spring groove, one end of the spring abutting against the bottom of the core-pulling base.

[0015] Furthermore, the hook is movably embedded inside the straight top block, and a stepped groove is provided on one side of the hook.

[0016] Furthermore, a second stepped groove is provided on one side of the core-pulling base, which fits into the first stepped groove, and a protrusion is provided at the top of the core-pulling body, with the top of the protrusion embedded inside the core-pulling base.

[0017] Furthermore, a core-pulling rod is movably provided inside the core-pulling body.

[0018] Furthermore, the inside of the straight top block is provided with a fixing hole that runs through the oblique guide groove, and a limit rod is provided inside the fixing hole.

[0019] Furthermore, the core-pulling body has a limiting hole inside that is movably sleeved with the limiting rod, and the limiting hole is elongated.

[0020] Furthermore, the inside of the straight push block is connected to a straight push rod by a straight push screw, the inside of the pull hook is provided with a pull hook screw, the core pull base is fixed to the core pull body by a base screw, and washers are fitted on the straight push screw, the pull hook screw and the base screw.

[0021] Furthermore, the core-pulling mechanism is mounted on the mold.

[0022] (III) Beneficial Effects

[0023] Compared with the prior art, this utility model provides a slanted core-pulling structure on the straight top of a two-color injection mold, which has the following beneficial effects:

[0024] This invention achieves efficient demolding of complex undercuts through the linkage design of the straight-push component and the inclined core-pulling component. The inclined guide groove composite track ensures that the core-pulling angle is precisely matched with the product demolding angle and increases the safety margin, ensuring the stability of the core-pulling stroke. The hook and core-pulling base, made of high-hardness material, are forcibly pulled through a mechanical interlocking structure, which significantly improves wear resistance and rigidity. At the same time, the self-lubricating mating surface reduces friction loss. The spring-assisted system thrust is optimized to match the core-pulling weight, ensuring complete demolding while preventing overload. The limit rod and floating guide system precisely control the stroke range. The overall structure is simple, compact, and highly efficient in debugging, and has broad application prospects. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the core-pulling mechanism and mold installation of this utility model;

[0026] Figure 2 This is a schematic diagram of the core-pulling mechanism of this utility model;

[0027] Figure 3 This is a schematic diagram of the inclined core-pulling assembly structure of this utility model;

[0028] Figure 4 This is a schematic diagram of the inclined core-pulling assembly structure of this utility model;

[0029] Figure 5 This is a schematic diagram of the inclined guide groove structure of this utility model;

[0030] Figure 6 This is a cross-sectional view of the core-pulling base structure of this utility model.

[0031] In the diagram: 1. Core-pulling mechanism; 11. Straight ejector assembly; 111. Straight ejector block; 112. Straight ejector rod; 113. Straight ejector screw; 114. Angled guide groove; 115. Spring groove; 116. Fixing hole; 117. Limiting rod; 12. Angled core-pulling assembly; 121. Core-pulling body; 1211. Protrusion; 122. Hook; 1221. Step groove one; 123. Core-pulling base; 1231. Step groove two; 124. Spring; 125. Core-pulling rod; 126. Base screw; 127. Hook screw; 128. Limiting hole; 13. Washer; 2. Mold. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] Example

[0034] like Figure 1-6 As shown in the figure, an embodiment of the present invention provides a slanted core-pulling structure on the straight top of a two-color injection mold, including a core-pulling mechanism 1, wherein the core-pulling mechanism 1 includes a straight top component 11 and a slanted core-pulling component 12 disposed inside the straight top component 11.

[0035] The direct-acting component 11 includes a direct-acting block 111, and the interior of the direct-acting block 111 is provided with an inclined guide groove 114.

[0036] The inclined core-pulling assembly 12 includes a core-pulling body 121 and a hook 122. The core-pulling body 121 is sleeved inside the inclined guide groove 114. One end of the inclined guide groove 114 is provided with a core-pulling base 123, and one end of the core-pulling base 123 is connected to one end of the hook 122.

[0037] The straight ejector block 111 has an internal inclined guide groove 114 forming a composite motion track, which enables the core-pulling body 121 to complete the lateral displacement synchronously along the inclined demolding angle when ejecting, realizing the forced demolding of the undercut structure. Through the linkage design of the straight ejector component 11 and the inclined core-pulling component 12, the space occupied by the traditional slider structure in the mold 2 is avoided. It is particularly suitable for the molding requirements of complex features such as inclined BOSS pillars. The processing steps are reduced, the EDM processing time is shortened, the overall production cycle is greatly reduced, and the installation and debugging time is also greatly reduced compared with the traditional structure.

[0038] like Figure 5 As shown, in some embodiments, the inside of the straight top block 111 is provided with spring grooves 115 located on both sides of the inclined guide groove 114, and the inclined core-pulling assembly 12 also includes a spring 124 disposed in the spring groove 115, one end of the spring 124 abutting against the bottom of the core-pulling base 123.

[0039] Spring 124 is pre-pressed at the bottom of core-pulling base 123. When hook 122 is released from constraint, it provides auxiliary thrust to ensure that core-pulling body 121 completes its final stroke and completely disengages from the product's undercut area. The force of spring 124 is precisely matched to the weight of the core-pulling body, controlled between 1.2 and 1.5 times the weight of core-pulling base 123 and core-pulling body 121, but not exceeding 40% of the weight of straight ejector block 111. This prevents insufficient demolding and avoids ejection overload, thereby improving the yield rate.

[0040] like Figure 2-6 As shown, in some embodiments, the hook 122 is movably embedded inside the straight top block 111. A stepped groove 1221 is provided on one side of the hook 122, and a stepped groove 1231 is provided on one side of the core-pulling base 123 that fits into the stepped groove 1221. A protrusion 1211 is provided at the top of the core-pulling body 121, and the top of the protrusion 1211 is embedded inside the core-pulling base 123.

[0041] The mechanical interlocking structure between the stepped groove 1221 and the core-pulling base 123 forces the core-pulling body 121 to move during the initial ejection stage, avoiding lag in oblique separation. The hook 122, treated with Cr12 tempering, enhances wear resistance and ensures core-pulling stability. The double-interlocking structure between the stepped groove 1231 and the protrusion 1211 enhances the rigidity between components. The self-lubricating design of the mating surface between the oblique guide groove 114 and the core-pulling base 123 reduces friction loss. The combination of the H13 quenched core-pulling body 121 (HRC58-60) and the core-pulling base 123 results in high forming surface precision. The length of the mating surface should be ≥1.5 times the demolding stroke. For example, a certain appliance shell mold uses a 20mm mating surface to ensure the stability of a 30mm core-pulling stroke.

[0042] like Figure 4-5 As shown, in some embodiments, a core-pulling rod 125 is movably disposed inside the core-pulling body 121, a fixing hole 116 is disposed inside the straight top block 111 that passes through the inclined guide groove 114, a limiting rod 117 is disposed inside the fixing hole 116, and a limiting hole 128 is disposed inside the core-pulling body 121 that is movably sleeved with the limiting rod 117, the limiting hole 128 being elongated.

[0043] The limiting rod 117 and the elongated limiting hole 128 form a floating guide system, which limits the maximum stroke of the core-pulling body 121 while allowing oblique sliding, preventing the core from falling off accidentally and ensuring no loss of reset accuracy, thus greatly reducing debugging time.

[0044] like Figure 1-2 As shown, in some embodiments, the inside of the straight push block 111 is connected to the straight push rod 112 by the straight push screw 113, the inside of the pull hook 122 is provided with the pull hook 122 screw, the core pull base 123 is fixed to the core pull body 121 by the base screw 126, and the straight push screw 113, the pull hook 122 screw and the base screw 126 are all fitted with washers 13.

[0045] M10 socket head cap screws, together with washer 13, secure the straight ejector rod 112, hook 122 and core-pulling base 123. The material combination of SKD61 straight ejector rod 112 and H13 ejector block optimizes the load-bearing strength. The bolt anti-loosening design improves production stability and extends the overall mold life.

[0046] like Figure 1 As shown, in some embodiments, the core-pulling mechanism 1 is installed on the mold 2. The core-pulling mechanism 1 and the mold 2 template are installed through a standardized interface, which is compatible with different models of injection molding machine top roller systems. It has strong structural compatibility and can be quickly deployed in molds 2 for various scenarios such as home appliances and automotive parts.

[0047] In use, complex undercut demolding is achieved through the linkage of the straight ejector assembly 11 and the inclined core-pulling assembly 12. When the injection molding machine ejector roller pushes the SKD61 straight ejector rod 112 to move vertically, the straight ejector block 111 rises. The inclined guide groove 114 converts the vertical force into an inclined component force, causing the H13 quenched core-pulling body 121 to move along a preset angle. The Cr12 hook 122 is mechanically interlocked with the stepped groove 1221 and the stepped groove 2 1231 to forcefully pull the core-pulling base 123, ensuring that the inclined feature is preferentially separated from the product. After the hook is released, the spring 124 pushes to complete the final stroke. The limit rod 117 and the elongated limit hole 128 control the movement range.

[0048] In summary, the linkage design of the straight push assembly 11 and the inclined core-pulling assembly 12 achieves efficient demolding of complex undercuts. The inclined guide groove 114 composite track ensures precise matching between the core-pulling angle and the product demolding angle, and increases the safety margin, ensuring the stability of the core-pulling stroke. The pull hook 122, made of high-hardness material, and the core-pulling base 123 are mechanically interlocked for forced traction, significantly improving wear resistance and rigidity. At the same time, the self-lubricating mating surface reduces friction loss. The spring 124 auxiliary system thrust is optimized to match the core-pulling weight, ensuring complete demolding while preventing overload. The limit rod 117 and the floating guide system precisely control the stroke range. The overall structure is simple, compact, and has high debugging efficiency, showing broad application prospects.

[0049] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A straight liftoff inclined core pulling structure of a two-color injection mold, comprising a core pulling mechanism (1), characterized in that: The core-pulling mechanism (1) includes a straight-push assembly (11) and an inclined core-pulling assembly (12) disposed inside the straight-push assembly (11); The direct-acting assembly (11) includes a direct-acting block (111), and the interior of the direct-acting block (111) is provided with an inclined guide groove (114); The oblique core-pulling assembly (12) includes a core-pulling body (121) and a hook (122). The core-pulling body (121) is fitted inside the oblique guide groove (114). One end of the oblique guide groove (114) is provided with a core-pulling base (123), and one end of the core-pulling base (123) is connected to one end of the hook (122).

2. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The straight top block (111) has spring grooves (115) located on both sides of the inclined guide groove (114) inside. The inclined core-pulling assembly (12) also includes a spring (124) disposed in the spring groove (115). One end of the spring (124) abuts against the bottom of the core-pulling base (123).

3. The inclined core-pulling structure on the straight top of a two-color injection mold according to claim 1, characterized in that: The hook (122) is movably embedded inside the straight top block (111), and a stepped groove (1221) is provided on one side of the hook (122).

4. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The core-pulling base (123) has a step groove two (1231) on one side that fits into the step groove one (1221), and the top of the core-pulling body (121) has a protrusion (1211), the top of the protrusion (1211) being embedded inside the core-pulling base (123).

5. The inclined core-pulling structure on the straight top of a two-color injection mold according to claim 1, characterized in that: The core-pulling body (121) is internally equipped with a core-pulling rod (125).

6. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The straight top block (111) has a fixing hole (116) that passes through the oblique guide groove (114) inside, and a limit rod (117) is provided inside the fixing hole (116).

7. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The core-pulling body (121) has a limiting hole (128) inside that is movably connected to the limiting rod (117), and the limiting hole (128) is elongated.

8. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The inside of the straight push block (111) is connected to the straight push rod (112) by the straight push screw (113). The inside of the pull hook (122) is provided with the pull hook (122) screw. The core pull base (123) is fixed to the core pull body (121) by the base screw (126). Washers (13) are all fitted on the straight push screw (113), the pull hook (122) screw and the base screw (126).

9. The inclined core pulling structure of the straight top of the two-color injection mold according to claim 1, wherein: The core-pulling mechanism (1) is installed on the mold (2).