An injection molding method with a thermistor connector

Abstract

This invention discloses an injection molding method for a thermistor connector, comprising: S1: fabricating the thermistor; S2: fixing the thermistor to one side of the terminal on a PCB board by means of a patch; S3: integrally injection molding the male connector terminal with plastic, wherein the plastic has a positioning groove adapted to the size of the thermistor; S4: assembling the terminal and plastic into a metal protective shell; S5: soldering the PCB board to the connector, at which point the thermistor is installed in the positioning groove, and then soldering the terminal and the PCB board; S6: soldering wires to the PCB board; S7: forming an inner mold and an outer mold, enclosing the metal protective shell, the rear end of the terminal, and the rear end of the PCB board within the inner and outer molds. The positioning groove provides protection for the thermistor, and an appropriate distance can be set between the thermistor and the positioning groove to suit the corresponding expansion coefficient of the thermistor, avoiding external interference and reducing the sensitivity value.

Description

Technical Field

[0001] This invention relates to the field of connector processing technology, and in particular to an injection molding method for a thermistor connector. Background Technology

[0002] Thermistors are a type of sensitive element, typically characterized by their sensitivity to temperature. In data cable products, thermistors need to be encapsulated in rubber through injection molding.

[0003] However, in existing thermistors, the thermistors are exposed on the PCB board (the side away from the terminals) during the molding process. Therefore, during actual injection molding or mold closing, the thermistors are prone to damage from compression (the thermistors are located on the side away from the inner mold, mainly due to interference from the terminals). Sometimes, the core wires connecting to the PCB board also break under pressure. Furthermore, the thermistors need to be encapsulated in the molding compound during injection molding. Since the molding temperature is around 180 degrees Celsius, this causes thermal shock to the thermistors, easily leading to failure or damage. Summary of the Invention

[0004] The main objective of this invention is to propose an injection molding method for a thermistor connector, aiming to improve the yield of thermistors by improving the injection molding method for thermistors.

[0005] To achieve the above objectives, the present invention proposes an injection molding method with a thermistor connector, comprising:

[0006] S1: Thermistor fabrication;

[0007] S2: The thermistor is fixed to one side of the terminal block on the PCB board by surface mounting;

[0008] S3: The terminals of the male connector are integrally injection molded with the plastic, and the plastic is provided with a positioning groove that is compatible with the size of the thermistor.

[0009] S4: Assemble the terminals and plastic into the metal protective shell;

[0010] S5: Solder the PCB board to the connector. At this time, the thermistor is installed in the positioning groove, and then the terminals and PCB board are soldered.

[0011] S6: Solder the wires onto the PCB board;

[0012] S7: The inner mold and outer mold are formed sequentially; the metal protective shell, the rear end of the terminal, and the rear end of the PCB board are wrapped inside the inner and outer molds.

[0013] Specifically, a predetermined gap is provided between the positioning groove of the inner mold and the outer wall of the thermistor.

[0014] Specifically, the PCB board has guide holes on both sides of the thermistor, and the inner mold has guide posts that cooperate with the guide holes; at the same time, the guide holes are modified to 5mm.

[0015] Specifically,

[0016] S7-1: The terminal has 4 parts, including a first terminal and a second terminal that are interconnected by a first connecting part, and a third terminal and a fourth terminal that are interconnected by a second connecting part; wherein the first terminal and the fourth terminal are connected to the connecting piece;

[0017] S7-2: The inner mold is formed by shaping the plastic and four terminals;

[0018] S7-3: The inner mold forming has cutting positions corresponding to the first connecting part and the second connecting part;

[0019] S7-4: The first and second connecting parts are cut off by passing the cutting machine through the cutting position, and then the next installation process is carried out.

[0020] The thermistor is positioned between the PCB board and the inner mold.

[0021] Specifically, in S7, when the thermistor and the inner mold are integrally injection molded, the outer wall of the thermistor is provided with a metal protective shell.

[0022] Specifically, in S7, the injection temperature of the inner mold is 180-220 degrees Celsius.

[0023] Specifically, the length of the terminal located in the middle is less than the length of the two sides, forming the first clearance position.

[0024] This invention mounts the thermistor on the PCB board near the male connector terminal, avoiding the problem of directly soldering the thermistor to the side without terminals (existing soldering methods reduce terminal interference and are simpler, but the thermistor is covered by plastic). Simultaneously, by pre-forming the inner mold, including the first and second clearance positions and the positioning groove, the terminals and plastic can avoid interfering with the thermistor, allowing it to be directly installed in the positioning groove. The positioning groove also protects the thermistor, and a suitable distance can be set between it and the positioning groove to accommodate the thermistor's expansion coefficient, preventing external interference and reducing sensitivity (avoiding thermal shock and compression from the inner mold injection). Furthermore, soldering the wire to the PCB board before forming the outer mold avoids the problem of insufficient protection due to short solder joints between the wire and PCB board, and the subsequently formed outer mold protects the solder joints, effectively improving subsequent processing of the male connector. Attached Figure Description

[0025] Figure 1 This is the processing design flow of the present invention;

[0026] Figure 2 This is illustration 1 of the prior art;

[0027] Figure 3 Figure 1 illustrates the present invention.

[0028] Figure 4 Illustration 2 is an example of existing technology;

[0029] Figure 5 Figure 2 shows the present invention;

[0030] Figure 6 Figure 3 shows the existing technology.

[0031] Figure 7 The terminal layout of this invention;

[0032] Figure 8 Schematic diagram of the terminals and inner mold after molding. Figure 1 ;

[0033] Figure 9 Illustration 4 shows the existing technology;

[0034] Figure 10 Schematic diagram of inner mold and terminal forming Figure 2 .

[0035] In the diagram, 1 is a thermistor, 2 is a PCB board, 3 is a terminal, 4 is an inner mold, 53 is a positioning groove, 61 is a guide hole, 62 is a guide post, 71 is the first connecting part, 72 is the second connecting part, 8 is the cutting position, and 9 is a metal protective shell. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0038] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are 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, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0039] Figure 1 This is the processing design flow of the present invention;

[0040] Figure 2 In the existing technology, the thermistor 1 is installed on the side away from the inner mold 4. Therefore, in actual processing, the thermistor 1 is placed downwards so that the terminal 3 on the other side of the PCB board 2 can be soldered and fixed. In this case, there will be some abnormal operation problems for the thermistor 1 (such as the PCB board 2 shifting, which will cause the thermistor 1 to collide with the side wall).

[0041] Figure 3 For the design of this invention, the thermistor 1 is installed on one side of terminal 3 of PCB board 2. By setting a first clearance position on terminal 3, the installation is facilitated. When soldering wires, the thermistor 1 does not have the problem of being subjected to force.

[0042] Figure 4 The mounting structure of the existing thermistor 1 is shown below;

[0043] Figure 5 This is the installation location of the present invention;

[0044] Figure 6 Terminal 3 is set independently, meaning that each terminal 3 is independent of the others;

[0045] Figure 7 The middle terminal 3 is provided with a first connecting part 71 and a second connecting part 72, thereby realizing the supporting function of the terminal 3;

[0046] Figure 8 After the terminal 3 and the inner curtain are formed, the first connecting part 71 and the second connecting part 72 are cut through the cutting position 8;

[0047] Figure 9 The terminals of the existing male connector are arranged in three rows;

[0048] Figure 10 The terminal 3 of the male connector of this application is arranged in a row.

[0049] like Figures 1 to 10 As shown, an injection molding method for having a thermistor connector includes:

[0050] S1: Thermistor fabrication;

[0051] S2: The thermistor is fixed to one side of the terminal block on the PCB board by surface mounting;

[0052] S3: The terminals of the male connector are integrally injection molded with the plastic, and the plastic is provided with a positioning groove that is compatible with the size of the thermistor.

[0053] S4: Assemble the terminals and plastic into the metal protective shell;

[0054] S5: Solder the PCB board to the connector. At this time, the thermistor is installed in the positioning groove, and then the terminals and PCB board are soldered.

[0055] S6: Solder the wires onto the PCB board;

[0056] S7: The inner mold and outer mold are formed sequentially; the metal protective shell, the rear end of the terminal, and the rear end of the PCB board are wrapped inside the inner and outer molds.

[0057] In specific embodiments, such as Figure 1 , Figure 2 as well as Figure 3 In contrast, mounting the thermistor 1 on the PCB board 2 on one side of the male connector terminal 3 avoids the existing method of directly soldering the thermistor 1 to the side without terminal 3 (the existing soldering method can reduce interference from terminal 3, and soldering terminal 3 is simpler, but part of the thermistor 1 will be covered by plastic); at the same time, by pre-forming the inner mold 4, the first clearance position, the second clearance position, and the positioning groove 53 are still pre-formed, so that terminal 3 and plastic can avoid interfering with the thermistor 1, thus allowing the thermistor 1 to be directly installed in the positioning groove 53. Meanwhile, the positioning groove 53 can... This design aims to protect the thermistor 1, and allows for a suitable distance between the thermistor 1 and the positioning groove 53. This distance is appropriate for the corresponding expansion coefficient of the thermistor 1, preventing external interference and reducing the sensitivity value (avoiding thermal shock and compression of the thermistor 1 during injection molding from the inner mold 4). Furthermore, by soldering the wire to the PCB board 2 before forming the outer mold, the problem of insufficient protection due to the short solder joint between the existing wire and PCB board 2 is avoided. The subsequently formed outer mold also protects the solder joint of the wire, effectively improving the subsequent processing of the male connector.

[0058] In a specific embodiment, a predetermined gap is provided between the positioning groove 53 of the inner mold 4 and the outer wall of the thermistor 1. In a preferred embodiment, the gap is 1mm-2mm, thereby ensuring the predetermined expansion coefficient of the thermistor 1 and also ensuring the protection of the thermistor 1.

[0059] Furthermore, the PCB board 2 has guide holes 61 on both sides of the thermistor 1, and the inner mold 4 has guide posts 62 that cooperate with the guide holes 61; at the same time, the guide holes 61 are modified to 5mm. This ensures the accurate insertion of the inner mold 4, and also ensures that the inner mold 4 is more stable after installation. The 5mm gap can play a better role in avoiding collisions.

[0060] In a specific embodiment, S7-1: There are four terminals 3, including a first terminal 3 and a second terminal 3 that are interconnected by a first connecting part 71, and a third terminal 3 and a fourth terminal 3 that are interconnected by a second connecting part 72; wherein the first terminal 3 and the fourth terminal 3 are connected to the connecting piece;

[0061] S7-2: The inner mold 4 is formed by molding the plastic and the four terminals 3;

[0062] S7-3: The inner mold 4 is formed with cutting positions 8 corresponding to the first connecting part 71 and the second connecting part 72;

[0063] S7-4: The first connecting part 71 and the second connecting part 72 are cut off by the cutting machine through the cutting position 8, and then the next installation process is carried out.

[0064] Because the second and third terminals correspond to the clearance positions of the thermistor 1, the problem that the existing thermistor 1 cannot be installed on the side with terminals is solved by setting the first connecting part 71, the second connecting part 72 and the cutting position 8. Moreover, this structure makes the injection molding of the terminal 3 simpler and more stable. Of course, in specific embodiments, the number of terminals 3 is not limited to 4, and multiple sets of terminals 3 can also be used. At the same time, the setting of the connecting part can play a better supporting role when the inner mold 4 is injected.

[0065] In this embodiment of the invention, the thermistor 1 is disposed between the PCB board 2 and the inner mold 4.

[0066] Specifically, in step S7, when the thermistor 1 and the inner mold 4 are integrally injection molded, the outer wall of the thermistor 1 is provided with a metal protective shell 9. The metal protective shell 9 can reduce external interference and influence on the thermistor 1, and can also effectively protect the thermistor 1 from external pressure and damage.

[0067] Furthermore, in S7, the injection temperature of the inner mold 4 is 180-220 degrees Celsius.

[0068] In this embodiment of the invention, the length of the terminal 3 in the middle is less than the length of the two sides, forming the first clearance position.

[0069] Technical table of thermistor 1 in this invention:

[0070]

[0071] In data cable applications, thermistor 1 needs to be encapsulated in a rubber compound through injection molding. The molding temperature of 180°C causes thermal shock to thermistor 1, which is composed of polymer and conductive particles. After special processing, the conductive particles form chain-like conductive paths within the polymer. When a normal operating current flows (or the component is at normal ambient temperature), the resettable fuse is in a low-resistance state. When an abnormal overcurrent flows through the circuit (or the ambient temperature rises), the heat generated by the large current (or increased ambient temperature) causes the polymer to expand rapidly, breaking the conductive path formed by the conductive particles, and the resettable fuse is in a high-resistance state. When the overcurrent (over-temperature condition) disappears, the polymer cools down, its volume returns to normal, and the conductive particles reform the conductive path, returning the resettable fuse to a high-resistance state. Similarly, when the overcurrent (over-temperature condition) disappears, the polymer cools down, its volume returns to normal, and the conductive particles reform the conductive path, returning the resettable fuse to its initial low-resistance state. Furthermore, the injection molding compound completely encapsulates the PTC, and the key change required for the thermistor to function properly is the rapid expansion of the polymer. However, the space needed for this expansion is consumed by the extrusion of the injection molding compound, resulting in the loss of its basic function.

[0072] This invention employs a hidden PTC protection design to prevent thermal shock and compression of the thermistor 1 during injection molding of the inner mold 4.

[0073] Actual test data for this invention:

[0074]

[0075] The hidden PTC protection design completely avoids the thermal shock and extrusion caused by injection molding, allowing the key properties of PTC to be fully utilized.

[0076] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An injection molding method for having a thermistor connector, characterized in that, include: S1: Thermistor fabrication; S2: The thermistor is fixed to one side of the terminal on the PCB board by surface mounting; S3: The terminals of the male connector are integrally injection molded with the plastic, and the plastic is provided with a positioning groove that is compatible with the size of the thermistor. S4: Assemble the terminals and plastic into the metal protective shell; S5: Solder the PCB board to the connector. At this time, the thermistor is installed in the positioning groove, and then the terminals and PCB board are soldered. S6: Solder the wires onto the PCB board; S7: The inner mold and outer mold are formed sequentially; the metal protective shell, the rear end of the terminal, and the rear end of the PCB board are encased in the inner mold and outer mold. S7 specifically refers to: S7-1: The terminal has 4 parts, including a first terminal and a second terminal that are interconnected by a first connecting part, and a third terminal and a fourth terminal that are interconnected by a second connecting part; wherein the first terminal and the fourth terminal are connected to the connecting piece; S7-2: The inner mold is formed by shaping the plastic and four terminals; S7-3: The inner mold forming has cutting positions corresponding to the first connecting part and the second connecting part; S7-4: The first and second connecting parts are cut off by passing the cutting machine through the cutting position, and then the next installation process is carried out. The length of the two middle terminals is less than the length of the terminals on both sides, forming the first clearance position.

2. The injection molding method with a thermistor connector as described in claim 1, characterized in that: A predetermined gap is provided between the positioning groove and the outer wall of the thermistor.

3. The injection molding method with a thermistor connector as described in claim 1, characterized in that: The PCB board has guide holes on both sides of the thermistor, and the inner mold has guide posts that cooperate with the guide holes.

4. The injection molding method with a thermistor connector as described in claim 1, characterized in that: The injection temperature in S3 is 180-220 degrees Celsius.

Images