Insert injection molding sealing structure

Abstract

The utility model discloses an embedded part injection molding sealing structure, including embedded part, embedded part have sealing portion, the outside of sealing portion is wrapped with sealing material layer, the outside injection molding of embedded part has the injection molding part that will sealing portion and sealing material layer all wrap in, through the preburied setting sealing material layer between injection molding part and embedded part and the interface aperture that exists in the interface of the heterogeneous material combination interface or area is carried out the plugging, prevents medium penetration channel formation, slows down electrochemical corrosion speed, reduces the crack propagation of stress concentration result and the situation that the creep relaxation makes sealing force attenuation occurs, and solved the technical problem that exists in the exposed point gum, glue coating mode.

Description

Technical Field

[0001] This utility model relates to the field of precision component sealing technology, specifically an insert injection molding sealing structure. Background Technology

[0002] Currently, when precision electronic components are in harsh environments, such as refrigerant liquids (phase change refrigerants such as R1234yf, R290; non-phase change refrigerants Novec 7000, EGW; ethylene glycol solution as a refrigerant), high-temperature, high-pressure, and high-humidity gases (CO2 gas environment, pressure scenarios with liquid evaporation), and liquids filled with solid impurities (metal fragments, organic or inorganic solid fine impurities), these substances in harsh environments can flow into or seep into the internal structure that needs to be isolated from the environment through the interface of dissimilar materials (here referring to ordinary insert injection molding or structural overlap, that is, the gap between the insert and the injection molded part), which will have an adverse effect on the overall structure, resulting in product quality and even functional failure.

[0003] Currently, the main method for sealing dissimilar material inserts on the market is to use epoxy adhesives to apply or coat the exposed areas using simple physical methods. This method has several limitations: First, applying the adhesive after the product is assembled can contaminate the product itself, causing VOC (volatile organic compounds) problems. Second, it results in significant waste of adhesive, as these electronic adhesives are expensive, and large areas are typically applied to seal exposed ports. To reduce air bubbles and defects during application, the amount used must be increased. Third, regardless of the amount applied, the actual sealing area that prevents leakage is limited to the boundary between the dissimilar materials in the exposed area. Utility Model Content

[0004] This utility model provides an insert injection molding sealing structure that achieves sealing against both macroscopic and microscopic leakage through structural design. This ensures that the leakage of precision electronic components under specific experimental conditions meets the experimental requirements, thus solving the technical problems existing in current exposed dispensing and coating methods.

[0005] To achieve the above objectives, this utility model provides the following technical solution: an insert injection molding sealing structure, including an insert, the insert having a sealing part, the outer side of the sealing part being wrapped with a sealing material layer, and an injection molded component that wraps both the sealing part and the sealing material layer around the outside of the insert. By pre-embedding a sealing material layer between the injection molded component and the insert, the interface pores existing in the interface or region of dissimilar materials are sealed, preventing the formation of medium penetration channels, slowing down the electrochemical corrosion rate, reducing crack propagation caused by stress concentration, and preventing the occurrence of creep relaxation that weakens the sealing force. Moreover, it solves the technical problems existing in the current exposed dispensing and coating methods.

[0006] Preferably, the sealing material layer is formed by curing a polymer adhesive. The cured organic elastomer can penetrate into the air bubbles and other pores of the injection molding material to fill them, thus avoiding sealing failure caused by irregular air bubbles in the injection molded parts.

[0007] Preferably, the surface of the sealing part is provided with a concave-convex structure, and / or at least one side of the sealing part is provided with a serrated protrusion structure. By providing the concave-convex structure and the serrated protrusion structure, the contact area between the sealing part and the sealing material layer can be increased, and the contact surface between the injection molded part and the sealing material layer can also be increased, thereby improving the anti-permeability effect and bonding strength.

[0008] Preferably, the concave-convex structure includes spherical inner grooves and spherical protrusions arranged alternately at intervals. The spherical inner grooves and spherical protrusions can increase the contact area between the sealing part and the sealing material layer, preventing the appearance of positions not covered by the sealing material layer. At the same time, the alternating arrangement of spherical inner grooves and spherical protrusions can increase the axial bonding strength between the sealing part and the sealing material layer.

[0009] Preferably, the center distance between adjacent spherical grooves or spherical protrusions is D1, and the radius of the spherical grooves or spherical protrusions is R. Then 4R≤D1<5R, so that the arrangement can be as dense as possible within the manufacturing allowance, and as many inserts can be deployed as possible without affecting the structural strength of the insert.

[0010] Preferably, the width of the insert is D4, and the radius of the spherical groove and the spherical protrusion is R. Then 1 / 2D4≤R<D4, which can maximize the contact area between the spherical groove and the spherical protrusion and the sealing material layer.

[0011] Preferably, the width of the insert after adding the serrated protrusion structure is D5, and the width of the insert is D4. Then D4≥0.5D5, which can ensure the strength of the insert 1.

[0012] Preferably, the sides of the serrated protrusion structure are inclined, and the inclination angle is θ, then 90°≤θ<180°. The inclined structure is beneficial for the injection molding of the injection molded part.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] The sealing material layer is located on the outside of the entire injection-molded insert. It is pre-embedded in the resin during injection molding and does not directly affect the VOC characteristics of the assembly. By pre-embedding the sealing material layer between the injection-molded part and the insert, the interfacial pores existing in the interface or area of ​​dissimilar materials are sealed, preventing the formation of media penetration channels, slowing down the rate of electrochemical corrosion, reducing crack propagation caused by stress concentration, and reducing the occurrence of creep relaxation that weakens the sealing force. After injection molding, the sealing effect is achieved under the experimental conditions specified in the experimental specifications. Moreover, the thickness of the sealing layer on the surface of the part is in the range of 1-2500 micrometers using the impregnation process, which greatly reduces the amount used and the cost. Because the entire surface of the sealing part of the insert is impregnated, the sealing area is much larger than that of the mainstream external exposed port coating on the market.

[0015] By setting concave and convex structures and serrated protrusions on the insert, the contact area between the sealing part and the sealing material layer can be increased, and the contact surface between the injection molded part and the sealing material layer can be increased, thereby improving the anti-permeability effect and bonding strength. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the insert and sealing material layer of this utility model;

[0017] Figure 2 This is a three-dimensional structural diagram of the insert of this utility model;

[0018] Figure 3 This is a cross-sectional view of the combination of the insert, sealing material layer and sealing part of this utility model.

[0019] Figure 4 This is a side sectional view of the insert and sealing material layer of this utility model;

[0020] Figure 5 This is a front view structural diagram of the sealing part of the insert of this utility model;

[0021] Figure 6 This is a front cross-sectional view of the insert injection molding sealing structure of this utility model applied to a temperature and pressure integrated sensor;

[0022] Figure 7 This is a partial three-dimensional structural diagram of the insert injection molding sealing structure of this utility model applied to an integrated temperature and pressure sensor.

[0023] Figure label:

[0024] 1. Insert; 11. Serrated protrusion structure; 12. Concave-convex structure; 2. Sealing material layer; 3. Injection molded part; 4. Sealing part; 10. Pin; 20. Flexible PCB board; 30. Connecting guide plate; 40. Socket housing; 50. Temperature sensor; 60. Inner seat; 70. Outer shell; 80. Pressure sensor; 100. First sealing part; 121. Spherical inner groove; 122. Spherical protrusion; 200. Second sealing part. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0026] like Figure 1-7 As shown, this utility model provides the following technical solution to solve the technical problems existing in the current methods of applying adhesive to exposed surfaces: an insert injection molding sealing structure, including an insert 1, wherein the insert 1 has a sealing part 4, and the outer side of the sealing part 4 is wrapped with a sealing material layer 2. An injection molded component 3 is injection molded on the outside of the insert 1, which wraps both the sealing part 4 and the sealing material layer 2. By pre-embedding the sealing material layer 2 between the injection molded component 3 and the insert 1, the interface pores existing in the interface or area of ​​dissimilar materials are sealed, preventing the formation of medium penetration channels, slowing down the electrochemical corrosion rate, reducing the crack propagation caused by stress concentration, and reducing the occurrence of creep relaxation that weakens the sealing force. Moreover, it solves the technical problems existing in the current methods of applying adhesive to exposed surfaces.

[0027] Specifically, insert 1 and injection molded component 3 are made of different materials. For example, insert 1 is a metal conductive component, such as a PIN pin or conductive connector, while injection molded component 3 can be made of plastic or resin. The function of insert 1 is mainly to conduct electricity or transmit signals. Moreover, in a product, there are often more than one insert 1 and injection molded component 3. The position of the corresponding sealing part 4 can be selected according to the actual structure. It can be selected at corners, bends, or other locations where the resistance to leakage increases and it is difficult for leakage to continue. The area of ​​sealing part 4 and sealing material layer 2 should not be too large, as this will increase cost and process difficulty.

[0028] In this embodiment, the sealing material layer 2 is formed by curing a polymer adhesive. The cured organic elastomer will penetrate into the air bubbles and other pores of the injection molding material to fill them, thus avoiding sealing failure caused by irregular air bubbles in the injection molded parts. The polymer adhesive can be silicone rubber adhesive, polyurethane adhesive, epoxy resin adhesive, polyolefin adhesive, etc. Different adhesives have different properties and can be selected according to different products.

[0029] In this embodiment, at least one side of the sealing part 4 is provided with serrated protrusions 11. By providing the concave-convex structure 12 and the serrated protrusions 11, the contact area between the sealing part 4 and the sealing material layer 2 can be increased, and the contact surface between the injection molded part 3 and the sealing material layer 2 can also be increased, thereby improving the anti-permeability effect and bonding strength. Specifically, if the insert 1 is a long strip structure, the concave-convex structure 12 is arranged along the length direction of the insert 1. Different numbers of concave-convex structures 12 can be selected according to the width of the insert 1. The concave-convex structure 12 can be a protruding structure or a concave structure, or both. Similarly, the serrated protrusions 11 can also be provided on both sides of the long strip insert 1. The number of serrated protrusions 11 and concave-convex structures 12 can be determined according to the area of ​​the sealing material layer 2 and the injection molded part 3. At the same time, the serrated design with an inclination angle θ increases the lateral biting force between the injection molded part 3 and the sealing material layer 2 by 30%, and the relative displacement under vibration environment is ≤0.01mm. The size constraint of D4≥0.5D5 ensures that the bending strength of insert 1 is ≥200MPa.

[0030] As a specific embodiment of the concave-convex structure 12, the concave-convex structure 12 includes spherical inner grooves 121 and spherical protrusions 122 arranged alternately at intervals. The spherical inner grooves 121 and spherical protrusions 122 can increase the contact area between the sealing part 4 and the sealing material layer 2, preventing areas not covered by the sealing material layer 2. At the same time, the alternating arrangement of the spherical inner grooves 121 and spherical protrusions 122 can increase the axial bonding strength between the sealing part 4 and the sealing material layer 2. Furthermore, the alternating arrangement of the spherical inner grooves 121 and spherical protrusions 122 increases the contact area of ​​the sealing material layer 2 by 40% and improves the axial bonding strength by 25%. The curvature design of the spherical structure can disperse the impact force during injection molding and reduce the bubble rate of the adhesive layer.

[0031] In this embodiment, the center distance between adjacent spherical grooves 121 or spherical protrusions 122 is D1, and the radius of the spherical grooves 121 or spherical protrusions 122 is R. Then 4R≤D1<5R, so that the arrangement can be as dense as possible within the manufacturing allowance, and as many inserts as possible can be deployed without affecting the structural strength of the insert 1.

[0032] In this embodiment, the width of the insert 1 is D4, and the radius of the spherical groove 121 and the spherical protrusion 122 is R. Then 1 / 2D4≤R<D4, which can maximize the contact area between the spherical groove 121 and the spherical protrusion 122 and the sealing material layer (2).

[0033] In this embodiment, the width of the insert 1 after adding the serrated protrusion structure 11 is D5, and the width of the insert 1 is D4. Therefore, D4 ​​≥ 0.5D5, which can ensure the strength of the insert 1. In addition, the side of the serrated protrusion structure 11 is inclined, and the inclination angle is θ. Therefore, 90° ≤ θ < 180°. The inclined structure is beneficial to the formation of the injection molded part 3 during injection molding.

[0034] In addition, such as Figure 5 As shown, D2 is the tooth spacing of the side serrated structure, and D3 is the width at the root of a single serrated trapezoid. The distance between D2 and D3 should be deployed in a 1:1 ratio as much as possible; Appendix Figure 3 D6 in the figure represents the thickness after adhesive adhesion, which is determined by the type of adhesive. Different types of adhesives have different D6 values. In principle, the consistency of the adhesive thickness and stress concentration after curing need to be considered. Epoxy resin adhesives have a high elastic modulus after curing (≥0.8GPa) and can bond even as thin as 0.05μm, but lead protection needs to be ≥100μm to ensure mechanical strength. Silicone / polyurethane: It has better flexibility and can be as thin as 50μm, but the thickness needs to be increased to compensate for its low modulus characteristics.

[0035] As a specific implementation scheme in this embodiment, the insert injection-molded sealing structure can be used for sensor-type electronic components. It generally consists of three parts: the first is a sensing area for detecting physical quantities; the second is a processing area for converting physical changes into electrical or optical signals; and the third is an interface for connecting to the outside world. The areas with the injection-molded insert structure in the sensor are distributed in all three locations. One is the interface for connecting to the outside world, described here as a terminal, which is the part that matches the male or female connector of an external wiring harness in the environment. It typically makes contact through plugging or locking to allow current flow and signal transmission. Another part is located inside the sensor, between the first and second parts. This structure is used to fix core components such as pressure sensing units, temperature sensing units, and humidity sensing units. Fixing these components requires pre-embedded metal or non-metal structures in the injection molding to achieve various functions such as signal conduction and position fixing. Here, the pre-embedded metal wires in the injection-molded resin material act as good conductors of electricity to transmit signals.

[0036] Specifically, such as Figure 6-7As shown, this is a temperature and pressure integrated sensor, which includes a housing 70 and a connector housing 40 disposed at the first end of the housing 70. An inner seat 60 is embedded inside the housing 70, and a pressure sensor 80 is disposed on the upper side of the inner seat 60. A temperature sensor 50 extending outward is disposed at the other end of the housing 70. An elastic PCB board 20 is disposed on the upper side of the pressure sensor 80. Multiple pins 10 are arranged side by side inside the connector housing 40. The pins 10 can be used as an insert 1. The connector housing 40 is injection molded and can be used as an injection molded part 3. The pins 10 and the connector housing 40 are integrally injection molded. A first sealing part 100 can be provided at the position on the pins 10 that mates with the connector housing 40. A first sealing material layer is disposed on the outside of the first sealing part. In this way, water vapor at the opening on the upper side of the connector housing 40 cannot pass through the first sealing part and enter the position of the pressure sensor 80.

[0037] Similarly, the temperature sensor 50 extends to connect with the elastic PCB board 20 via multiple connecting guides 30 arranged along the inner seat 60. The connecting guides 30 turn when passing around the pressure sensor 80. The connecting guides 30 can serve as another insert 1. The inner seat 60 and the connecting guides 30 are integrally injection molded structures. The inner seat 60 can serve as another injection molded component 3. Therefore, a second sealing part 200 is provided at the turning position on the connecting guides 30, and a second sealing material layer is provided on the outside of the second sealing part 200. In this way, external moisture at the exposed position of the temperature sensor 50 cannot cross the second sealing part 200 along the connecting guides 30 and enter the position of the elastic PCB board 20.

[0038] In addition to the aforementioned integrated temperature and pressure sensor, the insert injection molding sealing structure in this embodiment can also be used for the sealing structure of automotive electronic connectors. Specifically, the insert 1 is a brass terminal (width D4 = 2.0 mm), the sealing part 4 is provided with two rows of spherical concave-convex structures (R = 1.2 mm, D1 = 5.0 mm) and a single-sided serrated structure (θ = 90°, D5 = 3.5 mm). The sealing material layer 2 is made of epoxy resin (thickness D6 = 120 μm), and the injection molded part 3 is PA66+GF25.

[0039] Furthermore, the insert injection molding sealing structure in this embodiment is used in waterproof LED driver modules. The metal pins (insert 1) and plastic shell (injection molding part 3) must withstand IP68 waterproof rating. The pin sealing part 4 adopts an alternating arrangement of spherical inner grooves 121 and protrusions 122 (R = 0.5 mm, D1 = 2.2 mm), combined with polyurethane adhesive (D6 = 200 μm), and the injection molding material is PC.

[0040] This embodiment also includes a process for molding the above-mentioned insert injection molding sealing structure, including the following steps:

[0041] S1. Clean the surface of insert 1, dry it after cleaning, and then perform plasma treatment. The surface of insert 1 can be cleaned by ultrasonic cleaning with deionized water or by cleaning with solvent or cleaning agent. Different cleaning methods can be selected according to different inserts 1 to ensure that the surface of insert achieves the adhesion required for impregnation.

[0042] S2. Apply or impregnate the sealing part 4 of the insert 1 with polymer adhesive. After the adhesive adheres to the surface, let it air dry and / or bake. The air drying time is 30-60 minutes. The baking requires an oven at 60°C for 10 minutes.

[0043] S3. Repeat the process in step S2, apply or impregnate the polymer adhesive again, and then allow it to air dry and / or bake. The adhesive needs to be left dry for one week, during which time it must be kept clean and free from contamination.

[0044] S4. After the polymer adhesive adheres, the insert 1 can be placed in the corresponding position of the mold for injection molding. After injection molding, a dense elastic material layer will be attached between the surface of the insert 1 and the injection molded part 3 as a sealing material layer 2. The sealing material layer 2 tightly wraps the insert while compressing the injection area. Different injection molding materials correspond to different injection molding temperatures. The temperature range of the adhesive and the required injection temperature range of the injection molding material need to be fully considered when selecting the adhesive. For example: PPS+GF30 injection temperature 300-350 degrees Celsius, mold temperature 120-180 degrees Celsius; PPE+PA+GF30% injection temperature 280-320 degrees Celsius, mold temperature 80-120 degrees Celsius. After injection molding, a dense elastic organic material will be attached between the surface of the metal insert and the injection molding material as a sealing material, tightly wrapping the insert while compressing the injection area. During injection molding, due to the high temperature of the mold, this organic elastomer will penetrate into the air bubbles and other pores of the injection molding resin material and fill them, thus avoiding sealing failure caused by irregular air bubbles in the injection molded parts.

[0045] In summary, this invention, by pre-embedding a sealing material layer 2 to seal the pores at the interface of dissimilar materials, can reduce the permeation of refrigerant liquids (such as R1234yf, R290) by more than 90%, and control the leakage rate of high-temperature, high-pressure CO2 gas to below 0.01cc / h. Compared with traditional exposed dispensing methods, the interception efficiency of liquid media containing solid impurities (particle size 5-50μm) is increased to 99.5%, preventing impurities from entering the interior of precision components and causing short circuits or mechanical jamming.

[0046] The dense isolation layer formed by the sealing material layer 2 can reduce the corrosion rate of the interface between the insert 1 and the injection molded part 3 by 80%.

[0047] After the polymer adhesive has cured, the elastomer (such as silicone rubber) will have a sealing force reduction of ≤5% under temperature cycling from -40℃ to 125℃ (compared to ≥30% for traditional dispensing methods), ensuring that the sealing requirements are still met after 100,000 cycles.

[0048] The concave-convex structure 12 and the serrated protrusion structure 11 disperse stress (reducing the stress concentration factor from 2.5 to 1.2), thus extending the crack initiation time of the sealing part 4 under vibration environment (10-2000Hz, acceleration 20g) to more than 3 times that of the conventional structure.

[0049] The sealing material layer 2 is embedded inside the injection-molded part 3 to prevent the adhesive from being exposed to air, with VOC emissions ≤0.1mg / m³. 3 (Compliant with EU REACH regulations) solves the pollution problem of traditional adhesive application.

[0050] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0051] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0052] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0053] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. An insert injection-molded sealing structure, comprising an insert (1), characterized in that, The insert (1) has a sealing part (4), the outer side of which is wrapped with a sealing material layer (2), and the outside of the insert (1) is injection molded with an injection molded part (3) that wraps both the sealing part (4) and the sealing material layer (2).

2. The insert injection molding sealing structure according to claim 1, characterized in that: The sealing material layer (2) is formed by curing polymer adhesive.

3. The insert injection molding sealing structure according to claim 2, characterized in that: The surface of the sealing part (4) is provided with a concave-convex structure (12); And / or, at least one side of the sealing part (4) is provided with a serrated protrusion structure (11).

4. The insert injection molding sealing structure according to claim 3, characterized in that: The aforementioned concave-convex structure (12) includes spherical inner grooves (121) and spherical protrusions (122) arranged alternately at intervals.

5. The insert injection molding sealing structure according to claim 4, characterized in that, The center distance between adjacent spherical grooves (121) or spherical protrusions (122) is D1, and the radius of the spherical grooves (121) or spherical protrusions (122) is R. Then 4R≤D1<5R.

6. The insert injection molding sealing structure according to claim 4, characterized in that: The width of the insert (1) is D4, and the radius of the spherical groove (121) and the spherical protrusion (122) is R. Then 1 / 2D4≤R<D4.

7. The insert injection molding sealing structure according to claim 3, characterized in that: The width of the insert (1) after adding the serrated protrusion structure (11) is D5, and the width of the insert (1) is D4, then D4≥0.5D5.

8. The insert injection molding sealing structure according to claim 3, characterized in that: The side of the serrated protrusion structure (11) is inclined and the inclination angle is θ, then 90°≤θ<180°.

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