Insert injection molding method and new energy charging interface structure

Abstract

The present application relates to the technical field of automobile parts production, and in particular to an insert injection molding method and a new energy charging interface structure, comprising the following steps: step S1, positioning a copper nut in a cavity of a mold, positioning the copper nut by a first insert pin against a first end face of the copper nut and by a second insert pin against a second end face of the copper nut, so that the copper nut is accurately positioned in a clamped state; step S2, injecting plastic melt into the cavity until the melt is filled to a preset volume. The present application replaces the traditional process of glue fixing or hot fusion welding with double insert pin top positioning, combines copper nut positioning and injection molding into one, and eliminates additional processes such as glue coating, glue curing, copper nut preheating, and secondary hot pressing. Since the pure mechanical top positioning method is not affected by factors such as glue aging and temperature fluctuations, the axial position deviation of the copper nut is smaller.

Description

Technical Field

[0001] This invention relates to the field of automotive parts manufacturing technology, and more specifically to an insert injection molding method and a new energy charging interface structure. Background Technology

[0002] The rapid development of the new energy vehicle industry has placed extremely high demands on the manufacturing process of high-voltage charging interfaces. As a core component for energy replenishment in electric vehicles, the charging interface needs to withstand frequent plugging and unplugging operations over long-term use (typically requiring a plugging and unplugging force of ≥500N and a lifespan of ≥1500 cycles), while also meeting an IP67 or higher dustproof and waterproof rating to ensure the safety and reliability of the vehicle's electrical system. In this type of product, the copper nut, as a critical connector, typically needs to be embedded within a plastic housing for subsequent threaded locking with the charging gun. How to reliably and precisely fix the copper nut within the plastic substrate, ensuring that only one side is exposed while the remaining sides are completely encased in plastic, has become a key technical challenge in the industry.

[0003] To address the aforementioned needs, the industry currently primarily employs the following technological approaches: Firstly, thermoforming welding is one of the earliest methods used. The process involves injection molding a plastic shell, then heating a copper nut to a certain temperature at a pre-set hole and pressing it into the hole using a hot-pressing method. The advantages of this method are its simplicity and low equipment investment. However, it is essentially a physical interlocking rather than a molecular-level bond; the welding interface is merely a mechanical interlock between metal and plastic. Over long-term use, it is prone to loosening due to thermal cycling. Actual tests show that charging interfaces using thermoforming welding experience a torque attenuation of over 15% after 500 insertions and removals, and their sealing performance significantly deteriorates, making it difficult to meet the durability requirements of high-voltage systems in new energy vehicles.

[0004] To address the insufficient strength of hot-melt welding, the industry is gradually shifting towards insert injection molding, where copper nuts are pre-placed within the mold cavity before injection molding and then secured by the molten metal. The key to this process lies in ensuring precise positioning of the copper nuts during mold closing and injection molding. Common methods currently include temporary fixation with glue and interference fit fixation.

[0005] Temporary glue fixation involves applying glue to the outer wall of the copper nut to bond it to the mold insert. After injection molding, glue residue or carbonization may occur, but this does not affect product use. However, the glue is susceptible to aging; its adhesive strength decreases significantly under high-temperature injection molding conditions, and volatile substances from the glue may contaminate the mold cavity, affecting product appearance and consistency.

[0006] Interference fit fixing involves fitting a copper nut onto the mold insert with a small interference fit, using friction to maintain its position. However, the interference fit is greatly affected by temperature. After the mold is heated, the fit between the insert and the nut changes, which can easily lead to axial displacement of the nut (the measured displacement often exceeds 0.05mm), resulting in uneven plastic wall thickness or even perforation, or misalignment of the subsequent sealing groove, seriously affecting the product's sealing performance.

[0007] Both of these methods suffer from unreliable positioning and significant quality fluctuations. Industry statistics show that charging interface products using traditional insert injection molding generally have a first-pass yield of around 92%, with some companies even falling below 90%, resulting in high rework costs. Furthermore, because the insert remains stationary throughout the injection molding process and must wait for the plastic to completely cool and solidify before being removed, the entire molding cycle can exceed 110 seconds, leading to low production efficiency and making it difficult to meet the demands of large-scale production.

[0008] To address the problem of unstable positioning of copper nuts in traditional insert injection molding, various technical solutions have emerged in recent years that improve the insert structure. A review of existing patent literature reveals that these improvements mainly proceed in two directions: The first approach involves a pre-fixed structure for the insert and the copper nut. Some solutions employ threads or snap-fit ​​structures on the insert to create a mechanical connection between the copper nut and the insert before injection molding. For example, patent CN204773264U discloses a molding mechanism for a plastic nut. Its technical solution involves setting up an independent molding fixture, with its front end fixedly connected to the copper nut via threads. The rear end of the fixture is fixed inside the hollow channel of the mold insert. During injection molding, the insert is inserted into the cavity to position the copper nut. After the plastic part is molded, the molding fixture is rotated out of the plastic part. While this solution achieves reliable fixation of the copper nut during injection molding, it introduces an additional molding fixture and a rotation and disassembly process, complicating the process flow, limiting the improvement in production efficiency, and potentially causing secondary damage to the molded plastic during the rotation and removal operation.

[0009] The second direction is the integration of the fixing function of the insert itself. These improvements attempt to integrate adsorption or elastic fixing functions into the insert to replace glue or interference fit. For example, patent CN218748958U discloses a copper nut fixing device and a copper nut injection mold. It features an air suction unit inside the positioning insert, which uses air extraction to create negative pressure to adsorb the inner wall of the copper nut's hole, thus achieving fixation. This solution replaces adhesive with pneumatic adsorption, avoiding the problem of glue aging. However, it requires an additional air circuit system and sealing structure, and the adsorption force is affected by air pressure fluctuations, still posing a risk of loosening under high-pressure molten metal impact.

[0010] For example, patent CN220198399U discloses a device to prevent copper nuts from falling off during insert injection molding. It uses a U-shaped spring inside the insert pin to support the inner wall of the copper nut, while also incorporating a lateral clamping mechanism. This solution achieves fixation through mechanical elasticity and has a relatively simple structure. However, the spring is prone to fatigue due to prolonged heat, and multi-point contact may cause uneven force on the nut, affecting positioning accuracy.

[0011] A comprehensive analysis of the above technical solutions reveals that existing improvements primarily focus on how to fix the copper nut during injection molding. They all share a common characteristic: the insert remains stationary throughout the injection process, occupying the threaded hole position until the plastic is fully cured before retracting. This static fixing mode means that the top of the copper nut (the side in contact with the insert) can never be completely covered by plastic, resulting in an inherently exposed surface. Furthermore, the insert must wait for the plastic to cool sufficiently before retracting, making it difficult to shorten the injection cycle. Summary of the Invention

[0012] To address the technical problems existing in the prior art of insert injection molding, the first aspect of the present invention proposes a technical solution: an insert injection molding method, comprising the following steps: Step S1: Position the copper nut in the cavity of the mold, with the first insert pin pressing against the first end face of the copper nut and the second insert pin pressing against the second end face of the copper nut, so that the copper nut is precisely positioned in the mold-closed state. Step S2: Inject molten plastic into the cavity until the molten plastic fills to a preset volume. The preset volume is the volume of molten plastic when the cavity is completely filled, excluding the volume occupied by the second insert pin and the copper nut, as determined by a pre-test. Step S3: While keeping the first insert fixed, quickly pull the second insert out of the cavity to form a cavity in the filled melt that communicates with the second end face of the copper nut. Step S4: Continue injecting molten plastic for repair injection, filling the cavity tightly so that the plastic covers the five sides of the copper nut, with only the first end face exposed. Step S5: After cooling, open the mold and remove the molded product.

[0013] Preferably, in step S3, the extraction speed of the second insert is not less than 200 / s.

[0014] Preferably, in steps S3 and S4, steps S3 and S4 are performed continuously, and step S4 begins immediately after step S3 ends, without any time interval; in step S4, pressure is maintained after the plastic injection is completed, and the pressure maintenance time is not less than 3 seconds.

[0015] Preferably, in step S5, the cooling process and the pressure holding process in step S4 overlap at least partially.

[0016] Preferably, in step S2, the method for determining the preset volume includes: conducting a pre-test before batch injection molding, gradually controlling the injection machine to increase the injection volume and observing the melt filling state until the injection volume or the screw position of the injection machine is found to just fill all the cavities except for the volume of the second insert pin, and using this value as the control parameter for the preset volume.

[0017] Preferably, the first insert remains in a fixed position throughout the injection molding process. In step S3, the second insert is driven by a drive mechanism, which includes a cylinder or a hydraulic cylinder, and a high-speed solenoid valve is connected in series in its air or hydraulic circuit.

[0018] Preferably, the response time of the high-speed solenoid valve does not exceed 0.03 seconds.

[0019] Preferably, the surface of the second insert is provided with a TiN coating and the surface roughness Ra≤0.2μm.

[0020] The second aspect of the present invention proposes a technical solution, a new energy charging interface structure, including at least one copper nut, wherein the first end face of the copper nut is an assembly surface, and the new energy charging interface structure is formed by the above-mentioned insert injection molding method.

[0021] Preferably, after the new energy charging interface structure is injection molded, the axial position deviation of the copper nut in the new energy charging interface structure is ≤0.02 mm.

[0022] Compared with the prior art, the advantages of the present invention are as follows: This invention replaces the traditional process of glue fixing or hot melt welding with double-pronged top positioning, combining copper nut positioning and injection molding into one process. It eliminates additional processes such as glue application, glue curing, copper nut preheating, and secondary hot pressing, shortening the entire injection molding cycle from more than 110 seconds in the traditional process to less than 70 seconds, and improving production efficiency by about 40%.

[0023] Since the pure mechanical positioning method is not affected by factors such as glue aging and temperature fluctuations, the axial position deviation of the copper nut is ≤0.02mm, and the first-pass yield is increased from 92% of the traditional process to 99.7%, thereby reducing rework costs.

[0024] Furthermore, in this application, the second insert is dynamically withdrawn during the injection molding process, allowing the melt to fill the cavity during the pressure holding stage. This achieves a structure where all five sides of the copper nut are completely wrapped by plastic, with only the assembly surface exposed, forming a natural sealing step. After 1500 cycles of 500N insertion and removal abuse, it still meets the IP67 sealing rating, with torque attenuation ≤8%.

[0025] This invention uses a mechanical positioning method, eliminating the need for glue or interference fit, thus avoiding the risk of the insert breaking due to excessively tight bonding of the copper nut. It also eliminates the need for copper nut preheating and glue curing time, reducing overall mold energy consumption by more than 30%, which aligns with the development direction of green manufacturing. Attached Figure Description

[0026] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram showing how the first insert pin and the second insert pin are positioned in the insert injection molding method of the present invention for the copper nut; Figure 2 This is a schematic diagram of the second insert pin being extracted in the insert injection molding method shown in this invention; Figure 3 This is a schematic diagram of the insert injection molding method of the present invention, in which the plastic melt is continuously injected into the empty space inside the cavity to wrap the copper nut; Figure 4 This is a schematic diagram of the injection of molten plastic into the mold cavity in the insert injection molding method of the present invention; Figure 5 This is a schematic diagram of the new energy charging interface structure shown in this invention. Detailed Implementation

[0027] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0028] {Example 1} Combination Figures 1 to 3 As shown, the first aspect of the present invention proposes a technical solution, an insert injection molding method, comprising the following steps: Step S1: Position the copper nut M in the cavity 101 of the mold. The first end face of the copper nut M is pressed against by the first insert pin 13, and the second end face of the copper nut M is pressed against by the second insert pin 14, so that the copper nut M is accurately positioned in the mold closed state. Step S2: Inject plastic melt 201 into cavity 101 until the melt fills to a preset volume. The preset volume is the melt volume determined by a pre-test, which is the volume of the cavity when it is completely filled, excluding the volume occupied by the second insert pin 13 and the copper nut M. Step S3: While keeping the first insert pin 13 fixed, quickly pull the second insert pin 14 out of the cavity 101 to form a cavity in the filled melt that communicates with the second end face of the copper nut M. Step S4: Continue injecting molten plastic to fill the cavity completely, so that the plastic covers all five sides of the copper nut M, with only the first end face exposed. Step S5: After cooling, open the mold and remove the molded product.

[0029] The above-mentioned insert injection molding method is particularly suitable for various products that require precise encapsulation of metal inserts within a plastic matrix, especially for the manufacture of high-voltage charging interface structures for new energy vehicles (such as charging sockets).

[0030] In addition, this method can also be applied to other fields that require high-reliability insert injection molding, such as automotive electronic control unit (ECU) housings, battery management system (BMS) connectors, industrial waterproof connectors, medical device interfaces, and other plastic insert products that have strict requirements for sealing and mechanical strength.

[0031] Taking the new energy charging interface as an example, this product needs to withstand frequent plugging and unplugging, high voltage and high current impacts and harsh environmental tests during long-term outdoor use. This places extremely high demands on the positioning accuracy, wrapping integrity and sealing reliability of the copper nut. The insert injection molding method of this invention is designed for such demanding application scenarios.

[0032] The mold includes a moving mold 11 and a fixed mold 12. The first insert pin 13 is fixedly installed on one side of the moving mold 11. The installation method can be threaded connection or flange pressure plate fixation to ensure that the first insert pin 13 always remains stationary during the injection molding process. The front end face of the first insert pin 13 is flat and is used to abut against the first end face of the copper nut M (i.e. the final exposed assembly surface).

[0033] The second insert 14 is slidably mounted on one side of the fixed mold 12.

[0034] Optionally, the fixed mold 12 is provided with a guide sleeve, and the second insert 14 passes through the guide sleeve and can slide along the axial direction; the rear end of the second insert 14 is fixedly connected to the drive mechanism 30; the drive mechanism 30 is installed on the back of the fixed mold 12 and can be kept relatively fixed by a bracket.

[0035] Furthermore, the front end face of the second insert 14 is flat, used to abut against the second end face of the copper nut M (i.e., the inner end face covered by plastic). A precision fit clearance is provided between the guide sleeve and the second insert 14 to ensure smooth sliding and no molten material leakage.

[0036] Specifically, in combination Figure 1 As shown, in the mold-closed state, the moving mold 11 moves downward to the predetermined position, and the first insert pin 13 and the second insert pin 14 simultaneously abut against the copper nut M from both ends, so that the copper nut M is completely constrained in six degrees of freedom, achieving precise positioning and maintaining it in the predetermined position of the injection-molded product.

[0037] Compared to existing technologies that use adhesive bonding, interference fit connections, or improved pin structures, purely mechanical top restraint is unaffected by temperature, time, or media. Positioning accuracy is entirely guaranteed by the mold manufacturing precision, achieving an axial position deviation of no more than 0.02mm. Furthermore, the dynamic extraction of the second pin 14 allows the melt to fill the cavity, completely enveloping the copper nut except for its exposed end face.

[0038] Furthermore, in step 2, the total volume within the cavity 101 is defined as V0, where the volume occupied by the copper nut M is Vm and the volume occupied by the second insert 14 is V1. The cavity 101 is then divided into two parts: a fixed-size preset volume 101a and a variable preset volume 101b. The fixed-size preset volume 101a is V0-Vm, and the variable preset volume 101b is V1. The size of the fixed-size preset volume 101a needs to be calculated so that the second insert 14 can be removed when the fixed-size preset volume 101a is reached during the injection process.

[0039] Combination Figure 4 As shown, in an optional embodiment, in step S2, the method for determining the preset volume includes: conducting a pre-test before batch injection molding, gradually controlling the injection machine 20 to increase the injection volume and observing the melt filling state, that is, observing the height H of the melt from the top of the mold, until finding the injection volume or the screw position of the injection machine 20 when it just fills all the cavities except the volume of the second insert 14 (H=0), and using this value as the control parameter of the preset volume.

[0040] Using the screw position of injection molding machine 20 as the control parameter, the specific execution process is as follows: Preparation: Install the mold, set the injection molding machine 20 to manual or semi-automatic mode, and set the initial injection volume to 80% of the theoretical cavity volume (determined according to the proportion of the copper nut and the second insert 14 to the total volume of the part; the initial injection volume is slightly smaller than the volume excluding the copper nut and the second insert 14). Stepwise approximation test: Perform one injection cycle, observe the melt filling state after injection, and measure the distance H from the melt front to the top of the mold cavity (e.g., Figure 4 (as shown) If H>0 (i.e. not full), increase the injection volume in the next cycle (e.g., increase the screw stroke by 2% each time). If H < 0 (i.e., overfilling, which manifests as increased mold pressure), then reduce the injection volume; Repeat the above steps until you find the injection volume that makes H=0 (i.e., the melt just fills all the cavities except for the volume of the second insert 14).

[0041] Record control parameters: When the critical point of H=0 is found, record the screw position value L0 of the injection molding machine 20 at this time. The L0 value is the screw position control parameter corresponding to the preset volume.

[0042] Write to the control system: Input the L0 value into the controller of the injection molding machine 20 as the criterion for triggering the needle withdrawal action in step S2. In mass production, when the screw displacement reaches L0, the control system immediately sends a needle withdrawal signal.

[0043] Furthermore, in step S3, the extraction speed of the second insert 14 is not less than 200 mm / s.

[0044] It should be understood that at the moment the second insert 14 is withdrawn, the cavity formed behind it is under low pressure, and the surrounding melt tends to flow into the cavity. If the withdrawal speed is too slow, the flow front of the melt may catch up with the tail of the second insert 14, causing the melt to rush in before the second insert 14 has completely withdrawn, resulting in flow marks, turbulence, or uneven filling.

[0045] In this way, by extracting at high speed, it can be ensured that the withdrawal speed of the second insert 14 is much greater than the flow speed of the melt, so that the cavity is only filled after the second insert 14 has completely withdrawn, forming an orderly process of first emptying and then filling.

[0046] Furthermore, the first insert 13 remains in a fixed position throughout the injection molding process. In step S3, the second insert 14 is driven by the drive mechanism 30, which includes a cylinder or a hydraulic cylinder, and a high-speed solenoid valve is connected in series in its air or hydraulic circuit.

[0047] Among them, the response time of the high-speed solenoid valve is no more than 0.03 seconds.

[0048] This ensures that the timing of needle extraction matches the preset volume perfectly, achieving a seamless connection between steps S3 and S4.

[0049] Furthermore, the surface of the second insert 14 is coated with TiN, and the surface roughness Ra≤0.2μm.

[0050] Because the TiN coating has self-lubricating properties and a low coefficient of friction, it can significantly reduce the adhesion between the insert and the melt, making the needle-pulling action of the second insert 14 smoother, avoiding melt tearing or insert jamming caused by adhesion, and ensuring that the life of the second insert 14 is not less than 500,000 cycles.

[0051] Furthermore, in steps S3 and S4, the second insert 14 is immediately and without interval after being pulled out, and the pressure holding time during the plasticizing stage is not less than three seconds.

[0052] Specifically, the needle withdrawal action in step S3 and the plastic injection in step S4 are executed consecutively in sequence: the moment the second insert needle 14 retracts to its endpoint, the injection molding machine 20 immediately switches to the plastic injection stage, with no time buffer or waiting gap between the two. This seamless timing design ensures that the cavity is immediately filled by the subsequent melt after formation, avoiding problems such as backflow, collapse, or premature solidification of the melt due to pressure fluctuations.

[0053] Meanwhile, the holding time during the plasticizing stage should be no less than 3 seconds to ensure that the cavity is completely filled and there are no shrinkage cavities or air bubbles inside.

[0054] Furthermore, in step S5, the cooling process at least partially overlaps with the pressure holding process in step S4.

[0055] Since the second insert 14 has already withdrawn in step S3, there is no longer any insert occupying space in the mold cavity 101. The product does not need to wait for the insert to completely solidify before demolding during the cooling process, thus shortening the cooling time. Compared with the traditional process, the cooling process of the present invention is compressed to be executed in parallel with other processes (such as pressure holding and mold opening preparation), thereby shortening the entire production cycle.

[0056] It should be understood that the shortened injection molding cycle of the present invention does not solely rely on the reduction of cooling time, but rather on eliminating an indispensable additional step in the traditional process. Specifically: Traditional hot-melt welding process: First, a plastic shell needs to be injection molded, and then the copper nut is heated and pressed into the preset hole through hot pressing. The whole process includes two independent processing steps, which is time-consuming and energy-intensive.

[0057] Traditional glue-fixed insert injection molding process: Glue needs to be applied to the outer wall of the copper nut to bond and fix it to the mold insert. The glue application process itself takes time, and the glue needs to cure. At the same time, there are problems such as glue aging and volatile substances contaminating the mold.

[0058] The present invention combines the positioning of the copper nut M with the injection molding by mechanically positioning the first insert 13 and the second insert 14, eliminating the need for glue application, preheating, and secondary hot pressing, thus directly saving the glue application or hot melt welding process in the traditional process, thereby fundamentally shortening the whole mold injection cycle.

[0059] Taking a typical new energy charging interface product as an example, after adopting the method of this invention, the injection molding cycle of the whole mold can be controlled within 70 seconds (such as about 65 seconds). Compared with the traditional process of more than 110 seconds, the cycle is shortened by about 40%. This shortening of the cycle directly leads to the improvement of production efficiency and the reduction of energy consumption per piece, while avoiding quality hazards such as glue aging and pin breakage, as well as mold maintenance costs.

[0060] {Example 2} Combination Figure 5 As shown, the second aspect of the present invention proposes a technical solution, a new energy charging interface structure A, including at least one copper nut M, wherein the first end face of the copper nut M is an assembly surface, and the new energy charging interface structure A is formed by injection molding using the above-mentioned insert injection molding method.

[0061] After the injection molding of the new energy charging interface structure A is completed, the axial position deviation of the copper nut M in the new energy charging interface structure A is ≤0.02 mm.

[0062] As shown in the above-mentioned new energy charging interface structure A, the five sides of the copper nut M are completely wrapped by the plastic substrate, with only the assembly surface exposed, forming a natural sealed step structure that does not require secondary sealing treatment.

[0063] According to tests conducted by a third-party testing agency, the charging interface sample manufactured using the method of this invention passed 1500 cycles of 500N plug-in / plug-out abuse tests. Torque attenuation ≤8%, which is better than the industry standard requirement of ≤10%; The IP67 waterproof rating remains intact (no leakage during immersion test). The copper nut showed no signs of loosening or displacement.

[0064] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. An insert injection molding method, characterized in that, Includes the following steps: Step S1: Position the copper nut (M) in the cavity (101) of the mold, and use the first insert (13) to press against the first end face of the copper nut (M) and the second insert (14) to press against the second end face of the copper nut (M) so that the copper nut (M) is precisely positioned in the mold closed state. Step S2: Inject plastic melt into the cavity (101) until the melt fills to a preset volume. The preset volume is the melt volume determined by a pre-test when the cavity is completely filled, excluding the volume occupied by the second insert (13) and the copper nut (M). Step S3: While keeping the first insert (13) fixed, quickly pull the second insert (14) out of the cavity (101) to form a cavity in the filled melt that communicates with the second end face of the copper nut (M); Step S4: Continue to inject molten plastic for repair injection, filling the cavity tightly so that the plastic covers all five sides of the copper nut (M), with only the first end face exposed. Step S5: After cooling, open the mold and remove the molded product.

2. The insert injection molding method according to claim 1, characterized in that, In step S3, the extraction speed of the second insert (14) is not less than 200 mm / s.

3. The insert injection molding method according to claim 1, characterized in that, Steps S3 and S4 are performed consecutively, with step S4 starting immediately after step S3 ends, without any time interval. In step S4, pressure is maintained after the plastic injection is completed, and the pressure maintenance time is not less than 3 seconds.

4. The insert injection molding method according to claim 1, characterized in that, In step S5, the cooling process at least partially overlaps with the pressure holding process in step S4.

5. The insert injection molding method according to claim 1, characterized in that, In step S2, the method for determining the preset volume includes: conducting a pre-test before batch injection molding, gradually controlling the injection machine (20) to increase the injection volume and observing the melt filling state until the injection volume or the screw position of the injection machine (20) is found to just fill all the cavities except the volume of the second insert (14), and using this value as the control parameter of the preset volume.

6. The insert injection molding method according to claim 1, characterized in that, The first insert (13) remains in a fixed position during the injection molding process. In step S3, the second insert (14) is driven by a drive mechanism (30), which includes a cylinder or a hydraulic cylinder, and a high-speed solenoid valve is connected in series in its air or hydraulic circuit.

7. The insert injection molding method according to claim 6, characterized in that, The response time of the high-speed solenoid valve does not exceed 0.03 seconds.

8. The insert injection molding method according to claim 1, characterized in that, The surface of the second insert (14) is coated with TiN and has a surface roughness Ra≤0.2μm.

9. A new energy charging interface structure, comprising at least one copper nut (M), wherein the first end face of the copper nut (M) is a mounting surface, characterized in that, The new energy charging interface structure is formed by injection molding using the insert injection molding method described in any one of claims 1-8.

10. The new energy charging interface structure according to claim 9, characterized in that, After the new energy charging interface structure is injection molded, the axial position deviation of the copper nut (M) in the new energy charging interface structure is ≤0.02 mm.

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