Plugs, coupling plug structures, and plug assemblies

Abstract

The invention relates to a plug, a plug-in coupling structure and a plug assembly. The plug consists of: a connector (10) and a plug end (20); the plug end (20) consists of: a fixing part (21) and an elastic part (22); the fixing part (21) is constructed to be supplied on a coupling device (40); the connector (10) consists of one end electrically connected to the cable and the other end connected to the fixing part (21), wherein the elastic part (22) has an expandable insert hole for plugging in and electrically connecting to the coupling end. The plug has an elastic part with an expandable insert hole ensuring that the plug makes full contact with the coupling end and meets the mechanical and temperature rise requirements.

Description

Plug-in terminal, plug-in connection structure and plug-in terminal assembly

[0001] Related applications

[0002] This application claims priority to the Chinese invention patent application with application number 202110803188.3 filed on July 15, 2021, and the Chinese utility model patent application with application number 202121613410.5 filed on July 15, 2021, and cites their disclosed contents as part of this application. Technical Field

[0003] The present application relates to the field of electrical connection, and in particular to a plug-in terminal, a plug-in connection structure, and a plug-in terminal assembly. Background Art

[0004] Electric vehicles require a charging cable to be inserted into a charging station. The latest Chinese national standard stipulates that the force required to insert or remove a power plug from a power outlet, and a vehicle plug from a vehicle outlet, must meet national standards. Furthermore, the resistance of the terminals after insertion and the temperature rise during operation must meet standard requirements. Currently, most connectors on the market use wire spring holes or bow-shaped fins, resulting in complex structures and often failing to meet the required contact resistance and temperature rise. Consequently, numerous incidents have resulted in vehicle burns or damage to components due to issues with connector structure, temperature rise, and contact resistance, resulting in casualties and injuries to both the vehicle and personnel.

[0005] Therefore, a new solution is urgently needed in the prior art to solve the above problems.

[0006] Summary of the Invention

[0007] The present application provides a plug-in terminal, a plug-in connection structure, and a plug-in terminal assembly to solve the problem that existing plug-in terminals cannot meet mechanical requirements and temperature rise requirements.

[0008] An embodiment of the first aspect of the present application provides a plug-in terminal, comprising: a connecting end and a plug-in end; the plug-in end comprises a fixing unit and an elastic unit, the fixing unit being used to be arranged on a coupling device; one end of the connecting end can be electrically connected to a cable, and the other end of the connecting end is connected to the fixing unit; the elastic unit is provided with an expansion and contraction insertion hole, which is used to be plugged into a mating terminal and electrically connected to the mating terminal.

[0009] An embodiment of the second aspect of the present application provides a plug-in connection structure, which includes a mating terminal and the plug-in terminal as described above, the mating terminal is inserted into the expansion and contraction insertion hole, and the outer wall of the mating terminal is tightly fitted with the inner wall of the elastic unit.

[0010] An embodiment of a third aspect of the present application provides a plug-in terminal assembly, comprising the plug-in terminal as described above and a temperature sensor provided on the plug-in terminal.

[0011] This application can bring the following beneficial effects:

[0012] 1. The present application provides an elastic unit with an expansion and contraction insertion hole, so that the elastic unit can adapt to the processing error of the mating terminal, thereby increasing the bonding force between the plug-in terminal and the mating terminal, ensuring a larger contact area, and achieving better electrical and mechanical properties.

[0013] 2. This application provides a copper plug-in terminal and an aluminum connection terminal. The copper / copper alloy plug-in terminal can be directly plugged into the copper mating terminal. The copper mating terminal can then be connected to a copper wire. The aluminum / aluminum alloy connection terminal can be directly connected to an aluminum wire, thereby achieving a reliable connection between copper and aluminum conductors.

[0014] 3. The plug-in connection structure of the present application comprises a plug-in terminal made of copper / copper alloy and a connecting terminal made of aluminum / aluminum alloy, and a mating terminal comprising a contact section made of copper / copper alloy and a connecting section made of aluminum / aluminum alloy. When in use, the connecting terminal made of aluminum / aluminum alloy can be directly connected to the aluminum wire, and the connecting section made of aluminum / aluminum alloy can also be directly connected to the aluminum wire. The plug-in terminal made of copper / copper alloy is directly connected to the contact section made of copper / copper alloy. The copper plug-in structure can ensure the conductivity and stability of the electrical connection, and can better enable safe plug-in and unplugging of two aluminum wires.

[0015] 4. The present application designs the plug-in terminal as an elastic sheet structure with an expansion and contraction joint. When plugged into the mating terminal, the elastic sheet can not only adapt to the processing error of the mating terminal, but also, due to the elasticity of the elastic sheet, the plug-in terminal of the present application has a stronger bonding force with the mating terminal, ensuring a larger contact area and achieving better electrical and mechanical properties. This not only achieves effective contact connection, but also effectively reduces the hidden dangers of electric shock casualties and equipment damage caused by poor connector structure.

[0016] 5. The plug-in terminal of the present application has a positioning pin provided in the expansion-contraction insertion hole. The positioning pin can be plugged into and connected with the positioning hole of the mating terminal, so that the longer mating terminal can be positioned in the plug-in terminal, and the front end of the mating terminal will not shake in the expansion-contraction insertion hole of the plug-in terminal due to vibration. This prevents the change in contact resistance caused by shaking and maintains the current stability of the plug-in structure. It can also prevent the cables connected at the rear end from contacting each other due to excessive shaking of the mating terminal, causing a short circuit, thereby reducing the probability of short circuit accidents and electric shock casualties.

[0017] 6. In the plug-in terminal of the present application, the thickness of the elastic sheet on the side of the elastic unit opening is greater than the thickness of the elastic sheet on the side of the fixed unit. The thickness of the front end of the elastic sheet is increased, and the angle inside the front end of the elastic sheet is reduced. When the mating terminal is inserted, the internal plane of the front end of the expanded elastic sheet forms a surface contact with the surface of the mating terminal, thereby increasing the contact area between the two and ensuring the electrical performance of the plug-in terminal.

[0018] 7. The plug-in terminal of the present application has an inner hole cross-sectional area on one side of the fixed unit that is larger than the inner hole cross-sectional area on the open end, so that a tapered hole structure is formed inside the plug-in terminal. This allows the elastic unit to obtain a greater gripping force when plugged into the mating terminal. At the same time, it also allows the elastic unit to form a larger contact area with the surface of the mating terminal when it expands.

[0019] 8. The cross-sectional shape of the inner hole of the expansion and contraction insertion hole of the plug-in terminal of the present application is designed into various shapes, which facilitates designers to select plug-in terminals of different shapes according to the actual plug-in terminal arrangement environment, thereby reducing the volume of the plug-in structure, optimizing the contact area, and enhancing the electrical performance of the plug-in terminal;

[0020] 9. In the plug-in terminal of the present application, after the expansion and contraction insertion hole is plugged into the mating terminal, the inner surface of the expansion and contraction insertion hole at the position of the minimum inner diameter fits the outer surface of the mating terminal. When there is mud, sand, dirt, or foreign matter on the surface of the mating terminal, the inner surface of the plug-in terminal will scrape the surface of the mating terminal during plugging, effectively removing the mud, sand, dirt, and foreign matter on the surface of the mating terminal, ensuring that the elastic unit can effectively electrically connect to the surface of the mating terminal, and avoiding poor contact caused by impurities on the surface of the mating terminal.

[0021] 10. The plug-in terminal of the present application has an expansion and contraction insertion hole with a chamfer or rounded edge on the opening side, which can facilitate the insertion of the mating terminal;

[0022] 11. The plug-in terminal of the present application may be provided with an elastic kit. When the plug-in terminal itself is not elastic enough due to design reasons, the elastic kit may be used to supplement the gripping force of the plug-in terminal to the mating terminal;

[0023] 12. The plug-in terminal of the present application can be designed into a split structure, which is more convenient for processing and assembly;

[0024] 13. The plug-in terminal of this application adopts tellurium copper alloy, which makes the terminal have good conductivity and easy cutting performance, ensuring electrical performance and improving processability. At the same time, the tellurium copper alloy also has excellent elasticity;

[0025] 14. The plug-in terminal of the present application adopts a coating, which can better enhance the corrosion resistance. Preferably, a composite coating is adopted, which can better enhance the firmness of the coating and ensure that the coating does not fall off and is corrosion-resistant after multiple plugging and unplugging.

[0026] 15. The plug-in terminal of the present application, by setting the elastic sheet into a corrugated structure, not only increases the contact area between the elastic sheet and the mating terminal, thereby enhancing the electrical performance of the plug-in terminal, but also has an axial positioning effect on the mating terminal, preventing the mating terminal from falling out of the expansion and contraction insertion hole, thereby improving safety and reliability.

[0027] 16. The temperature sensor can penetrate deep into the terminal to obtain the most accurate temperature value of the plugged terminal, thereby helping the staff understand the temperature condition of the terminal during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. In the drawings:

[0029] FIG1 is a schematic structural diagram of the plug-in terminal of the present application installed in a coupling device;

[0030] FIG2 is a schematic structural diagram of a plug-in terminal and a mating terminal of the present application;

[0031] FIG3 is a schematic structural diagram of a plug-in terminal of the present application;

[0032] FIG4 is a schematic diagram of another structure of a plug terminal of the present application;

[0033] FIG5 is a schematic structural diagram of a plug-in end of a plug-in terminal according to the present application;

[0034] FIG6 is a schematic structural diagram of a plug-in terminal with an elastic kit according to the present application;

[0035] FIG7 is a schematic structural diagram of a plug-in terminal connection end of the present application;

[0036] FIG8 is a schematic structural diagram of another connecting end of a plug terminal of the present application;

[0037] FIG9 is a schematic structural diagram of another plug-in terminal and another mating terminal of the present invention;

[0038] FIG10 is a schematic structural diagram of an embodiment of the present application in which a plug end has a through hole;

[0039] FIG11 is a schematic structural diagram of another plug-in terminal and another mating terminal of the present application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail with reference to the accompanying drawings. Here, the schematic embodiments of the present invention and their description are used to explain the present invention, but are not intended to limit the present invention. Among them, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "multiple" means two or more. In the description of this application, unless otherwise specified, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms in this patent can be understood according to the specific circumstances.

[0041] An embodiment of the first aspect of the present application provides a plug-in terminal, as shown in Figures 1 and 3, comprising: a connecting end 10 and a plug-in end 20; the plug-in end 20 comprises a fixing unit 21 and an elastic unit 22, and the fixing unit 21 is arranged on a coupling device 40; one end of the connecting end 10 is electrically connected to the cable, and the other end is connected to the fixing unit 21; as shown in Figures 2 and 5, the elastic unit 22 is provided with an expansion and contraction insertion hole 223 for plugging with the mating terminal 30 and electrically connecting with the mating terminal 30.

[0042] The present application sets up an elastic unit with an expansion and contraction insertion hole, so that the elastic unit can adapt to the processing error of the mating terminal, so that the bonding force between the plug-in terminal of the present application and the mating terminal is greater, ensuring a larger contact area, achieving better electrical and mechanical properties, and solving the problem that the existing plug-in terminals cannot meet the mechanical requirements and temperature rise requirements.

[0043] Due to the high voltage and current in electric vehicle cables, large-diameter wires are required for current transmission. However, with rising copper prices, the material cost of using copper as conductors is increasing. Therefore, the search for alternatives to copper metal to reduce costs has begun. Aluminum accounts for approximately 7.73% of the Earth's crust. With optimized extraction technology, its price is relatively low. Furthermore, aluminum is lighter than copper and has a conductivity second only to copper, making it a suitable replacement for copper in electrical connections. Therefore, replacing copper with aluminum is a growing trend in automotive electrical connections.

[0044] However, due to the large electrode potential difference between copper and aluminum, electrochemical corrosion will occur between the copper and aluminum wires after they are directly connected. Aluminum is susceptible to corrosion, resulting in increased resistance in the connection area, which can easily lead to serious consequences in electrical connections, such as functional failure and fire.

[0045] To solve the problem in the prior art that copper and aluminum wires are difficult to connect reliably, in some embodiments, the connecting end 10 is made of aluminum or aluminum alloy, and the plug end 20 is made of copper or copper alloy.

[0046] In this embodiment, a plug-in end made of copper / copper alloy and a connecting end made of aluminum / aluminum alloy are provided. The plug-in end made of copper / copper alloy can be directly plugged into the mating terminal made of copper, the mating terminal made of copper can be connected to a copper wire, and the connecting end made of aluminum / aluminum alloy can be directly connected to an aluminum wire, thereby achieving a reliable connection between the copper and aluminum conductors and solving the problem of difficulty in reliably connecting the copper and aluminum conductors.

[0047] Furthermore, the connection end 10 and the fixing unit 21 are connected together by friction welding, ultrasonic welding, arc welding, laser welding, resistance welding or several other methods.

[0048] Friction welding refers to a method of welding that uses the heat generated by friction between the contact surfaces of the workpieces as a heat source to cause the workpieces to undergo plastic deformation under pressure.

[0049] Ultrasonic welding uses high-frequency vibration waves to transmit to the surfaces of two objects to be welded. Under pressure, the two surfaces of the objects rub against each other to form a fusion between the molecular layers.

[0050] Arc welding refers to the use of electric arc as a heat source and the physical phenomenon of air discharge to convert electrical energy into the thermal energy and mechanical energy required for welding, thereby achieving the purpose of connecting metals. The main methods include arc welding, submerged arc welding, gas shielded welding, etc.

[0051] Laser welding is an efficient and precise welding method that uses a high-energy-density laser beam as a heat source.

[0052] Resistance welding refers to a method of welding that uses a strong current to pass through the contact point between the electrode and the workpiece, generating heat due to the contact resistance.

[0053] By adopting the above processing methods or combinations, the plug-in terminal made of copper / copper alloy and the connecting terminal made of aluminum / aluminum alloy can be effectively connected, ensuring that the plug-in terminal has good mechanical and electrical properties.

[0054] In some embodiments, the elastic unit 22 includes a copper segment and an aluminum segment. One end of the aluminum segment is fixedly connected to the copper segment, and the other end is connected to the fixing unit.

[0055] Furthermore, the length of the copper segment accounts for 0.5% to 99.9% of the entire length of the elastic insert unit.

[0056] Aluminum is lightweight. As long as the contact part with the mating terminal is copper, the rest can be made of aluminum, which contributes to the overall lightweight design.

[0057] The inventors tested 10 plug-in terminals of the same shape and expansion joint width. Each terminal had a different proportion of copper segments, with the length of the copper segments accounting for 0.4%, 0.5%, 5%, 15%, 40%, 60%, 80%, 90%, 95%, and 99.9% of the overall length of the plug-in elastic unit, respectively. The conductivity results are shown in Table 1. Generally, a conductivity above 99% is considered ideal.

[0058] Table 1 Relationship between the ratio of the copper segment length to the overall length of the elastic unit and the conductivity

[0059] Ratio 0.4% 0.5% 5% 15% 40% 60% 80% 90% 95% 99.9% Conductivity 98.5% 99% 99.1% 99.5% 99.7% 99.7% 99.8% 99.8% 99.9% 99.9%

[0060] As can be seen from Table 1, when the length of the copper segment accounts for less than 0.5% of the overall length of the plug elastic unit, the conductivity decreases a lot. When the length of the copper segment accounts for 0.5% of the overall length of the plug elastic unit, the conductivity can reach the ideal value, which can ensure normal current transmission between the terminals. In addition, in order to ensure that the contact portion with the mating terminal 30 is copper, the length of the copper segment accounts for less than or equal to 99.9% of the overall length of the plug elastic unit. Therefore, the inventor sets the length of the copper segment to 0.5% to 99.9% of the overall length of the plug elastic unit.

[0061] In some embodiments, the coupling device 40 can be the tip of a charging gun, and the plug-in terminal is detachably mounted on the tip of the charging gun via the fixing unit 21. One end of the connecting end 10 can establish an electrical connection with the cable, and the other end is connected to the fixing unit 21. The elastic unit 22 of the plug-in end 20 has an expansion-contraction insertion hole 223 formed within it, which can accommodate the mating terminal 30 of the charging base and establish an electrical connection with the mating terminal 30. See Figures 1 and 2.

[0062] In some embodiments, the elastic unit 22 includes an expansion joint 221 extending in the longitudinal direction of the plug terminal, and the expansion joint 221 divides the elastic unit 22 into elastic pieces 222, as shown in FIG5 .

[0063] When the mating terminal 30 is inserted along the elastic unit 22, the elastic sheet 222 expands axially as the insertion depth increases, and due to the stress, the inner surface of the elastic sheet 222 adheres to the surface of the mating terminal 30. The elastic sheet 222 not only accommodates machining errors in the diameter of the mating terminal 30, but also, due to the elasticity of the elastic sheet 222, the plug-in terminal of the present application and the mating terminal 30 have a stronger bonding force, ensuring a larger contact area and achieving better electrical and mechanical properties. This not only achieves effective contact connection, but also effectively reduces the hidden dangers of electric shock casualties and equipment damage caused by poor connector structure.

[0064] Furthermore, as shown in FIG9 , each elastic sheet 222 extends in a corrugated shape in the longitudinal direction, i.e., each elastic sheet 222 has a corrugated structure. Accordingly, the outer wall surface of the mating terminal 30 extends in a corrugated shape in the axial direction to fit closely with the elastic sheet 222. By providing the elastic sheet 222 with a corrugated structure, the contact area between the elastic sheet 222 and the mating terminal 30 is increased, thereby enhancing the electrical performance of the plug-in terminal. In addition, the mating terminal 30 is axially positioned to prevent it from falling out of the expansion and contraction insertion hole 223, thereby improving safety and reliability.

[0065] In some embodiments, as shown in Figure 4 , the width of the expansion joint 221 on the side near the fixed unit 21 is greater than or equal to the width on the side near the opening of the elastic unit 22. On the side near the opening of the elastic unit 22, where the elastic sheet 222 and the mating terminal 30 come into contact, the smaller the gap of the expansion joint 221 on the side near the opening of the elastic unit 22, the better. Furthermore, since the expansion and contraction insertion hole 223 can allow water and sediment to enter, a location for draining sediment and water should be designed on the plug-in terminal to improve performance and extend its service life. Therefore, the wider the expansion joint 221 on the side near the fixed unit 21, the better the drainage performance.

[0066] Furthermore, the minimum width of the expansion joint 221 ranges from 0.01mm to 12mm. The inventors conducted extensive experiments on the minimum width of the expansion joint 221 of plug-in terminals of varying diameters, demonstrating that if the minimum width of the expansion joint 221 is less than 0.01mm, water and sediment within the plug-in terminal will be difficult to drain, resulting in internal blockage and scratches on the plug-in terminal surface. In severe cases, this can increase contact resistance and sharply increase temperature, potentially causing circuit burnout. If the minimum width of the expansion joint 221 is greater than 12mm, the width of the elastic piece 222 is too small, and the contact area with the mating terminal 30 is also too small, failing to meet the required electrical conductivity area for the plug-in terminal and failing to achieve optimal electrical conductivity for the circuit.

[0067] Furthermore, the minimum width of the expansion joint 221 ranges from 0.1 mm to 10 mm. Similarly, the inventors have optimized the minimum width range of the expansion joint 221 based on experimental results, which can ensure the electrical conductivity of the plug terminal while also allowing for the timely removal of water and sediment inside the plug terminal, thereby extending the service life of the plug terminal.

[0068] The number of the elastic sheets 222 is 4, 6, 8, 10, 12, 14, or 16. Since the electrical connection between the plug terminal and the mating terminal 30 is ensured by the elasticity of the elastic sheets 222, it is best to arrange the elastic sheets 222 symmetrically to ensure symmetrical stress after contact. Therefore, the number of the elastic sheets 222 is generally an even number.

[0069] The inventors selected 100 plug-in terminals of the same material, shape, and expansion / contraction gap width. They set the number of elastic segments 222 on the plug-in terminals to 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20, respectively, with each group containing 10 plug-in terminals. The inventors tested the electrical conductivity of the plug-in terminal samples after mating and the elastic force on the opening side of the elastic unit 22. The test results are shown in Table 2.

[0070] The conductivity test method is to pass the same current through the plug-in terminal and the mating terminal 30 after insertion, and compare the current value after detection with the current value detected when the plug-in terminal and the mating terminal 30 are in full contact. In this embodiment, a ratio less than 99% is considered unqualified.

[0071] The spring force test method uses a precision dynamometer to measure the spring force required to move the opening of a single elastic piece 222 by 1mm. In this embodiment, depending on the terminal shape, a spring force less than 3N or greater than 10N is considered unacceptable. Low spring force weakens the grip of the mating terminal 30, reducing the contact area and increasing contact resistance. High spring force increases the insertion force of the mating terminal 30, making it difficult to insert or remove the terminal.

[0072] Table 2 Effect of different numbers of elastic sheets on conductivity and elastic force

[0073]

[0074] As can be seen from Table 2 above, when the number of elastic sheets 222 is less than four, the conductivity is excellent due to the large width of the elastic sheets 222, but the elasticity is poor, making it difficult to insert and remove the mating terminal 30. When the number of elastic sheets 222 increases to 16 or more, the increased expansion and contraction gaps 221 reduce the contact area, and the conductivity also fails to meet the requirements. Furthermore, due to the small width of the elastic sheets 222, the elastic force cannot be guaranteed. Therefore, the inventors have determined the number of elastic sheets 222 to be 4, 6, 8, 10, 12, 14, or 16.

[0075] The cross-sectional area of ​​the inner hole of the expansion and contraction insertion hole 223 of the elastic unit 22 on the side close to the fixed unit 21 is larger than the cross-sectional area of ​​the inner hole at the open end of the elastic unit 22. If the inner diameter of the expansion and contraction insertion hole 223 is exactly the same as the outer diameter of the mating terminal 30, due to tolerance matching, the mating terminal 30 may not be inserted into the expansion and contraction insertion hole 223, or the mating terminal 30 and the expansion and contraction insertion hole 223 may have a large area that is not in contact, resulting in failure to achieve electrical conduction, or the small contact area leads to increased contact resistance and excessive circuit temperature rise. Therefore, the inventors set the interior of the expansion and contraction insertion hole 223 to be a cone with a small opening and a large rear end, so that the mating terminal 30 can be inserted into the expansion and contraction insertion hole 223, and at the same time, the elastic sheet 222 can have a larger deformation space, so that the elastic unit 22 and the mating terminal 30 can obtain a greater gripping force after being plugged in.

[0076] As shown in FIG4 , the elastic piece 222 forms a cone angle with the axis of the plug end 20 . Preferably, the cone angle of the elastic piece 222 is 0.1°-30°.

[0077] If the cone angle is less than 0.1°, the width of the expansion joint 221 is basically the same, which may result in the expansion joint 221 at the front end of the elastic unit 22 being wider, and the contact area with the mating terminal 30 being small, resulting in increased contact resistance and excessive line temperature rise, etc., or the width of the expansion joint 221 on the side close to the fixed unit 21 is too small, resulting in the inability to discharge water and mud inside the plug terminal in time, thereby reducing the service life of the plug terminal.

[0078] If the cone angle is greater than 30°, the width of the expansion and contraction joint 221 will differ greatly. When the width of the expansion and contraction joint 221 at the front end of the elastic unit 22 is narrow, the width of the expansion and contraction joint 221 on the side close to the fixed unit 21 is too large, resulting in a smaller width of the elastic sheet 222. The elastic force of the elastic sheet 222 is insufficient and the gripping force with the mating terminal 30 cannot be guaranteed.

[0079] The thickness of the elastic sheet 222 on the side of the opening of the elastic unit 22 is greater than the thickness on the side close to the fixing unit 21 .

[0080] If the thickness of the elastic sheet 222 is uniform, after the expansion and contraction insertion hole 223 of the elastic unit 22 is plugged into the mating terminal 30, the inner surface of the expansion and contraction insertion hole 223 at the location of the minimum inner diameter of the expansion and contraction insertion hole 223 will mate with the outer surface of the mating terminal 30, forming a linear contact with a small contact area. Therefore, the inventors increased the thickness of the front end of the elastic sheet 222 and reduced the angle of the interior of the front end of the elastic sheet 222. After the mating terminal 30 is inserted, the expanded front end of the elastic sheet 222 forms a surface contact with the surface of the mating terminal 30, increasing the contact area between the two and ensuring the electrical performance of the plug-in terminal.

[0081] After the expansion and contraction insertion hole 223 of the elastic unit 22 is plugged into the mating terminal 30, the inner surface of the expansion and contraction insertion hole 223 at the position of the minimum inner diameter is in contact with the outer surface of the mating terminal 30. The mating terminal 30 is generally a male terminal. When used in a harsh environment or in the outside world for a long time, if mud, sand, dirt, or foreign matter are deposited on the surface of the mating terminal 30, if not treated, it will not only affect the contact effect between the plug terminal and the mating terminal 30 and reduce electrical performance, but also cause damage to the surfaces of both, destroy the plating, and greatly shorten the life of the plug terminal. In severe cases, the contact resistance will increase, causing the plug connector to overheat and burn, resulting in a safety accident. The inner surface of the minimum inner diameter position of the expansion and contraction insertion hole 223 fits with the outer surface of the mating terminal 30. When plugged in, the inner surface of the plug-in terminal will scrape the surface of the mating terminal 30, which can effectively remove mud, dirt and foreign matter on the surface of the mating terminal 30, so that the two can be in closer contact and achieve better electrical performance.

[0082] In some embodiments, as shown in Figure 11, a positioning pin 52 is provided in the expansion and contraction insertion hole 223, and the positioning pin 52 is used to be plugged into and connected with the positioning hole 51 at the front end of the mating terminal 30, so that the longer mating terminal can be positioned in the plug-in terminal, so that the front end of the mating terminal 30 will not shake in the expansion and contraction insertion hole of the plug-in terminal due to vibration, that is, the contact resistance change caused by shaking is prevented, and the current stability of the plug-in structure is maintained; it can also avoid the mating terminal from shaking too much, causing the cables connected at the rear end to contact each other and cause a short circuit, thereby reducing the chance of short circuit accidents and electric shock casualties.

[0083] Furthermore, the positioning pin 52 is arranged along the axial direction of the expansion and contraction insertion hole 223, and the positioning pin 52 is fixed on the end wall of the expansion and contraction insertion hole 223. The positioning pin 52 has a top and a bottom connected to the end wall. The cross-sectional area of ​​the top is less than or equal to the cross-sectional area of ​​the bottom. Accordingly, the front end aperture of the positioning hole 51 of the mating terminal 30 is larger than the rear end aperture to match the shape of the positioning pin 52 for easy insertion.

[0084] Specifically, the elastic unit 22 includes an insertion section, an extension section and a solid section connected in sequence, the expansion and contraction insertion hole 223 is formed inside the insertion section and the extension section, the solid section is connected to the fixing unit 21, and the positioning pin 52 is provided on the side of the solid section close to the extension section to facilitate plugging with the positioning hole 51 at the front end of the mating terminal 30.

[0085] In some embodiments, the cross-sectional shape of the inner hole of the expansion and contraction insertion hole 223 of the elastic unit 22 is circular, elliptical, polygonal, flat, E-shaped, F-shaped, H-shaped, K-shaped, L-shaped, T-shaped, U-shaped, V-shaped, W-shaped, X-shaped, Y-shaped, Z-shaped, semi-arc-shaped, arc-shaped, or wavy. The cross-sectional shape of the inner hole of the expansion and contraction insertion hole 223 is designed to be various shapes to facilitate designers to select different shapes of plug terminals according to the actual plug terminal layout environment, reduce the volume of the plug structure, optimize the contact area, and enhance the electrical performance of the plug terminals.

[0086] In some embodiments, the expansion and contraction insertion hole 223 of the elastic unit 22 is provided with a chamfer or fillet on the inner side of the opening of the elastic unit 22. Since the expansion and contraction insertion hole 223 is generally a tapered hole, the opening diameter of the expansion and contraction insertion hole 223 is smaller than the diameter of the mating terminal 30. Therefore, a chamfer or fillet is provided on the inner side of the opening of the expansion and contraction insertion hole 223 to guide the insertion of the mating terminal 30, so that the mating terminal 30 can be smoothly inserted and the elastic piece 222 can be expanded and inserted into the expansion and contraction insertion hole 223.

[0087] In some embodiments, as shown in FIG. 5 and FIG. 6 , the elastic unit 22 has a circumferentially arranged groove 224 on the outside, the groove 224 corresponds to the expansion and contraction insertion hole 223 , and the plug terminal further includes an elastic sleeve 225 for being sleeved on the groove 224 .

[0088] It should be noted that when the plug-in terminal is designed to be too thin due to the use environment, or has a large number of openings, or has a large diameter difference with the mating terminal 30, the elastic sheet 222 will not have sufficient grip on the mating terminal 30, resulting in a small contact area between the plug-in terminal and the mating terminal 30 and poor electrical performance. When the plug-in terminal itself lacks elasticity due to design reasons, an elastic kit 225 can be used to supplement the grip of the plug-in terminal on the mating terminal 30. The elastic kit 225 can be an elastic rubber body or an open elastic rigid body, which can limit the further outward expansion of the elastic sheet 222 of the plug-in terminal, thereby increasing the grip of the elastic sheet 222 on the mating terminal 30.

[0089] As shown in Figure 6, the outer wall of the plug end 20 has a groove 224 arranged along the circumference. The groove 224 is an annular groove. At least one elastic sleeve 225 is sleeved on the groove 224 to fasten the plug end 20 so that the elastic unit 22 fits better with the mating terminal 30.

[0090] In some embodiments, the plug end 20 and the connection end 10 are integrally formed. The integrally formed design has high strength and, more importantly, can be centrally processed and assembled, greatly improving assembly efficiency.

[0091] The connecting end 10 and the plug-in end 20 are connected by crimping, clamping, threading, welding, riveting or embedding.

[0092] Crimping is a production process in which the connecting terminal 10 and the plug terminal 20 are assembled and then pressed together using a crimping machine. The advantage of crimping is mass production. By using chain terminals and automatic crimping machines, it is possible to quickly produce large quantities of products with stable quality.

[0093] The clamping is to clamp the connecting end 10 and the plug end 20 together using a clamp or other components. The advantage of the clamping is that it does not require complex equipment and can be connected with the help of tools, which is suitable for scenes such as repair and maintenance.

[0094] The threaded connection is that the connecting end 10 and the plug end 20 each have a threaded structure and can be screwed together, or connected together using a separate stud and nut. The advantage of the threaded connection is detachability, which allows repeated assembly and disassembly, and is suitable for scenarios that require frequent disassembly.

[0095] Welding is carried out by friction welding, resistance welding, ultrasonic welding, arc welding, pressure welding, laser welding, explosion welding, and the connecting end 10 and the plug end 20 are melted into a whole through metal welding points, so the connection is firm and the contact resistance is small.

[0096] Riveting is to use rivets to rivet the connecting end 10 and the plug end 20 together. The advantages of riveting are firm connection, simple processing method and easy operation.

[0097] Embedded connection means that the connection end 10 and the plug end 20 have an embedded structure at the connection point, which can be embedded and assembled together. The advantage of embedded connection is that no tools are required, and only the connection end 10 and the plug end 20 need to be assembled together, which is suitable for scenes such as repair and maintenance.

[0098] In some embodiments, due to the special design of the coupling device 40, the integrated plug-in terminal cannot be assembled into the coupling device 40, so the plug-in terminal needs to be made into a split structure and assembled and connected on the coupling device 40. At this time, crimping, snap-on, threaded connection, riveting or embedded connection are more suitable.

[0099] In some embodiments, due to the complex structure of the plug-in terminal, the high cost and long processing time of the integrated processing method, the plug-in terminal can be divided into several parts for processing. For example, the plug-in terminal 20 can be processed by stamping, and the connecting terminal 10 can be processed by machining. The two can then be assembled together. This can simplify the process, reduce processing costs, and shorten processing time.

[0100] The connecting end 10 is a flat plate structure (as shown in FIG. 2 and FIG. 7 ), a U-shaped structure, an arc-shaped structure, a cylindrical structure (as shown in FIG. 3 ), a columnar structure (as shown in FIG. 1 ), a bowl-shaped structure, or a polygonal structure (as shown in FIG. 8 ).

[0101] In some embodiments, the connector 10 needs to be electrically connected to the cable, typically by crimping or welding. Therefore, the connector 10 can be designed in a variety of structures. Depending on the electrical connection requirements and the assembly environment of the coupling device 40, different connector 10 structures can be selected to establish a stable electrical connection with the cable. Generally, a U-shaped structure, an arc-shaped structure, a cylindrical structure, or a polygonal structure is suitable for crimping and welding, while a flat plate or bowl-shaped structure is suitable for welding.

[0102] In some embodiments, the material of the connecting end 10 and / or the plug end 20 contains tellurium.

[0103] Furthermore, the tellurium content in the material of the connecting end 10 and / or the plug end 20 is 0.1%-5%.

[0104] In other words, the plug end 20 is made of a tellurium-copper alloy, which provides the terminal with good electrical conductivity and easy-to-cut properties, ensuring both electrical performance and improved machinability. Furthermore, the tellurium-copper alloy also has excellent elasticity. Preferably, the tellurium content of the tellurium-copper alloy is 0.2%-1.2%.

[0105] The inventors tested 10 plug-in terminals of identical shape and expansion joint width. Each terminal was made of a tellurium-copper alloy with tellurium contents of 0.05%, 0.1%, 0.2%, 1%, 1.2%, 1.8%, 3%, 5%, 6%, and 7%, respectively. The test results are shown in Table 3. In this embodiment, the tellurium-copper alloy exhibited an ideal conductivity of greater than 99%.

[0106] Table 3. Effect of tellurium-copper alloys with different tellurium contents on electrical conductivity.

[0107] Tellurium content 0.05% 0.1% 0.2% 1% 1.2% 1.8% 3% 5% 6% 7% Electrical conductivity 98.6% 99.1% 99.3% 99.6% 99.8% 99.5% 99.3% 99.1% 98.9% 98.7%

[0108] As shown in Table 3, when the tellurium content is less than 0.1% or greater than 5%, the conductivity decreases significantly and fails to meet the ideal value requirements. When the tellurium content is greater than or equal to 0.2% and less than or equal to 1.2%, the conductivity is the best. Therefore, the inventors selected a tellurium-copper alloy with a tellurium content of 0.1%-5%. In the most ideal case, a tellurium-copper alloy with a content of 0.2%-1.2% is selected.

[0109] The connection end 10 and / or the plug end 20 are provided with a coating to improve corrosion resistance, improve electrical conductivity, increase the number of plugging and unplugging, and better extend the service life of the connection end 10 and the plug end 20.

[0110] The coating can be formed by electroplating, chemical plating, magnetron sputtering, or vacuum plating. The coating thickness on the connecting end 10 and the plug end 20 is consistent. The consistent coating thickness allows for a single electroplating process during processing, eliminating the need for complex electroplating processes to obtain different coating thicknesses in different areas. This saves processing costs and reduces electroplating pollution.

[0111] Electroplating is the process of plating a thin layer of other metals or alloys on certain metal surfaces using the principle of electrolysis.

[0112] The chemical plating method is a process of depositing metal through a controllable redox reaction under the catalytic action of the metal.

[0113] Magnetron sputtering utilizes the interaction of magnetic and electric fields to cause electrons to spiral near the target surface, thereby increasing the probability of electrons striking argon gas to generate ions. These ions, under the influence of the electric field, collide with the target surface, sputtering the target material.

[0114] The vacuum plating method is to deposit various metal and non-metallic films on the surface of plastic parts through distillation or sputtering under vacuum conditions.

[0115] The material of the plating layer on the connecting end 10 is different from the material of the plating layer on the plug end 20 .

[0116] The plating material is one or more of gold, silver, nickel, tin, zinc, tin-lead alloy, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver and silver-gold-zirconium alloy. Copper, as an active metal, will undergo oxidation reaction with oxygen and water during use. Therefore, one or more inactive metals are required as plating to extend the service life of the plug-in terminal. In addition, for metal contacts that need to be frequently plugged in and out, better wear-resistant metals are also required as plating, which can greatly increase the service life of the contacts. In addition, the contacts need to have good electrical conductivity. The conductivity and stability of the above metals are better than those of copper or copper alloys, which can enable the plug-in terminals to obtain better electrical performance and longer service life.

[0117] Since the plug end 20 is frequently plugged in and out of the mating terminal and is also electrically connected to the mating terminal, the plating material here is generally a metal material with excellent conductivity, stability, and wear resistance. However, such metals are generally precious metals and are relatively expensive. The connection end 10 is where the conductor of the cable is electrically connected. Stability and wear resistance are not required, so some metal materials with excellent performance, but low price and mass production can be used as the plating material.

[0118] To demonstrate the impact of different plating materials on the overall performance of plug-in terminals, the inventors used sample plug-in terminals of the same specifications and material, but with different plating materials, and conducted a series of plug-in and pull-out cycle and corrosion resistance tests using matching connectors of the same specifications. To demonstrate the advantages and disadvantages of the selected materials and other commonly used electroplating materials, the inventors also used tin, nickel, and zinc as plating materials in the experiments. The experimental results are shown in Table 4 below.

[0119] The plugging and unplugging times listed in Table 4 below are simulated by fixing the terminals on a test bench and using a mechanical device to simulate plugging and unplugging them. After every 100 plugging and unplugging cycles, the test was stopped to observe damage to the terminal surface plating. If the terminal surface plating was scratched and the terminal material was exposed, the test was stopped and the plugging and unplugging times at that time were recorded. A plugging and unplugging cycle of less than 8,000 cycles was considered unqualified.

[0120] The corrosion resistance time test in Table 4 below involved placing the plug terminals in a salt spray test chamber. Salt spray was applied to various locations on the terminals. The terminals were removed, cleaned, and observed for surface corrosion every 20 hours. This constituted a cycle. Testing was stopped until the surface corrosion area exceeded 10% of the total terminal area. The number of cycles was recorded. In this example, a cycle of less than 80 cycles was considered unsatisfactory.

[0121] Table 4: Effects of different plating materials on the plug-in and plug-out times and corrosion resistance of plug terminals

[0122]

[0123] As can be seen from the table above, when gold, silver, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy were used as the coating materials, the experimental results significantly exceeded the standard values, and the performance was relatively stable. When nickel, tin, tin-lead alloy, and zinc were used as the coating materials, the experimental results also met the requirements. Therefore, the inventors selected gold, silver, nickel, tin, tin-lead alloy, zinc, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy as the coating materials, or a combination thereof.

[0124] The plating layer includes a bottom layer and a surface layer.

[0125] In some embodiments, the coating is coated using a multi-layer coating method. After processing, the connecting end 10 and / or the plug end 20 still have many gaps and holes under the surface microscopic interface. These gaps and holes are the biggest cause of wear and corrosion of the connecting end 10 and / or the plug end 20 during use. Therefore, it is necessary to first coat a bottom layer on the surface of the connecting end 10 and / or the plug end 20 to fill the gaps and holes on the surface, so that the surface of the connecting end 10 and / or the plug end 20 is smooth and free of holes, and then coat the surface layer. The bonding will be stronger and smoother, and the coating surface will have no gaps and holes, so that the wear resistance, corrosion resistance, and electrical performance of the plug terminal are better, greatly extending the service life of the plug terminal.

[0126] The bottom layer material is one or more of gold, silver, nickel, tin, tin-lead alloy and zinc; the surface layer material is one or more of gold, silver, nickel, tin, tin-lead alloy, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver and silver-gold-zirconium alloy.

[0127] In another embodiment, the bottom layer has a thickness of 0.01 μm to 15 μm. Preferably, the bottom layer has a thickness of 0.1 μm to 9 μm.

[0128] In another embodiment, the thickness of the surface layer is 0.5 μm-55 μm. Preferably, the thickness of the surface layer is 1 μm-35 μm.

[0129] To demonstrate the effect of variations in bottom-layer plating thickness on the overall performance of plug-in terminals, the inventors used plug-in terminal samples of the same specifications and material, with different nickel-plated bottom-layer thicknesses and the same silver-plated surface thickness, and conducted a series of temperature rise and corrosion resistance time tests using mating connectors of the same specifications. The experimental results are shown in Table 5 below.

[0130] The temperature rise test in Table 5 below involves passing the same current through the mating terminal and the mating terminal 30. The temperature at the same location on the mating terminal before power application and after temperature stabilization is measured in a closed environment, and the absolute value of the difference is taken. In this embodiment, a temperature rise greater than 50K is considered unqualified.

[0131] The corrosion resistance time test in Table 5 below involved placing the plug terminals in a salt spray test chamber. Salt spray was applied to various locations on the terminals. The terminals were removed for cleaning and observed for surface corrosion every 20 hours. This constituted a cycle. Testing was stopped until the surface corrosion area exceeded 10% of the total terminal area. The cycle count was then recorded. In this example, a cycle count of less than 80 was considered unsatisfactory.

[0132] Table 5: Effect of different base coating thickness on temperature rise and corrosion resistance of plug terminals

[0133]

[0134] As can be seen from Table 5 above, when the thickness of the underlying nickel plating layer is less than 0.01 μm, although the temperature rise of the plug-in terminal is qualified, due to the thin coating, the number of corrosion resistance cycles of the plug-in terminal is less than 80, which does not meet the performance requirements of the plug-in terminal. This has a great impact on the overall performance and life of the docking plug, and in severe cases, it causes a sudden reduction in product life or even failure and combustion accidents. When the thickness of the underlying nickel plating layer is greater than 15 μm, due to the thick underlying coating, the heat generated by the plug-in terminal cannot be dissipated, making the temperature rise of the plug-in terminal unqualified. Moreover, the thick coating is more likely to fall off from the terminal surface, resulting in a decrease in the number of corrosion resistance cycles. Therefore, the inventors selected a bottom coating thickness of 0.01 μm-15 μm. Preferably, the inventors found that when the bottom coating thickness is 0.1 μm-9 μm, the combined effect of the temperature rise and corrosion resistance of the plug-in terminal is better. Therefore, in order to further improve the safety, reliability and practicality of the product itself, the bottom coating thickness is preferably 0.1 μm-9 μm.

[0135] To demonstrate the effect of changes in surface plating thickness on the overall performance of plug-in terminals, the inventors used plug-in terminal samples of the same specifications and materials, with the same nickel-plated base thickness and different silver-plated surface thicknesses, and used mating connectors of the same specifications to conduct a series of temperature rise and corrosion resistance time tests. The experimental results are shown in Table 6 below.

[0136] The experimental method is the same as the above experimental method.

[0137] Table 6: Effect of different surface coating thicknesses on temperature rise and corrosion resistance

[0138]

[0139] It can be seen from Table 6 above that when the thickness of the surface silver plating layer is less than 0.5 μm, although the temperature rise of the plug-in terminal is qualified, the number of corrosion resistance cycles of the plug-in terminal is less than 80 because the plating layer is too thin, which does not meet the performance requirements of the plug-in terminal. The overall performance and life of the docking plug are greatly affected. In severe cases, it causes a sudden reduction in product life or even failure and combustion accidents. When the thickness of the surface silver plating layer is greater than 55 μm, due to the thicker underlying plating layer, the heat generated by the plug-in terminal cannot be dissipated, making the temperature rise of the plug-in terminal unqualified, and the thicker plating layer is more likely to fall off from the terminal surface, resulting in a decrease in the number of corrosion resistance cycles. In addition, since the surface plating metal is more expensive, using a thicker plating layer does not improve the performance and has no use value. Therefore, the inventors selected a surface silver plating layer thickness of 0.1 μm-55 μm.

[0140] Preferably, the inventors found that when the surface coating thickness is 1 μm-35 μm, the combined effect of temperature rise and corrosion resistance of the plug terminal is better. Therefore, in order to further improve the safety, reliability and practicality of the product itself, the surface coating thickness is preferably 1 μm-35 μm.

[0141] The present application changes the structure of the plug end and designs the plug end 20 to have a structure with an expansion and contraction joint 221 and an elastic piece 222, and changes the surface structure of the elastic piece 222, so that when it is used, it can not only achieve effective contact connection, but also effectively reduce the hidden dangers of electric shock casualties and equipment damage caused by poor connector structure.

[0142] As shown in FIG2 , an embodiment of the second aspect of the present application provides a plug-in connection structure, comprising a mating terminal 30 and a plug-in terminal according to the first embodiment. The mating terminal 30 is inserted into the expansion and contraction insertion hole 223, and the outer sidewall of the mating terminal 30 is tightly fitted with the inner sidewall of the elastic unit 22. The plug-in terminal of the plug-in connection structure has the same structure, operating principle, and beneficial effects as the plug-in terminal of the first embodiment, and will not be further described here.

[0143] In some embodiments, the connecting end 10 is made of aluminum or aluminum alloy, and the plug-in end 20 is made of copper or copper alloy; the mating terminal 30 includes a contact section 31 and a connecting section 32 connected to each other, the contact section 31 is made of copper or copper alloy, and the connecting section 32 is made of aluminum or aluminum alloy. The contact section 31 is inserted into the expansion and contraction insertion hole 223, and the outer wall of the contact section 31 is tightly fitted with the inner wall of the elastic unit 22, and the connecting section 32 is located outside the expansion and contraction insertion hole 223.

[0144] As shown in Figure 2, when in use, the connecting end 10 of the plug-in terminal made of aluminum / aluminum alloy can be directly connected to the aluminum wire, the connecting section 32 of the mating terminal 30 made of aluminum / aluminum alloy can also be directly connected to the aluminum wire, and the plug-in end 20 of the plug-in terminal made of copper / copper alloy is directly connected to the contact section 31 of the copper / copper alloy of the mating terminal 30.

[0145] As shown in FIG2 , further, the contact segment 31 and the connection segment 32 are connected together by friction welding, ultrasonic welding, arc welding, laser welding, resistance welding or several other methods.

[0146] As shown in FIG. 2 , further, an insulating protective cap 50 is provided at the front end of the contact section 31 .

[0147] In other embodiments, the connecting end 10 is made of aluminum or aluminum alloy, and the plug-in end 20 is made of copper or copper alloy; the mating terminal 30 includes a contact section 31 and a connecting section 32 connected to each other, and the mating terminal 30 is made of copper or copper alloy, and the contact section 31 is inserted into the expansion and contraction insertion hole 223, and the outer wall of the contact section 31 is tightly fitted with the inner wall of the elastic unit 22, and the connecting section 32 is located outside the expansion and contraction insertion hole 223.

[0148] As shown in Figure 2, when in use, the connecting end 10 of the plug-in terminal made of aluminum / aluminum alloy can be directly connected to the aluminum wire, and the connecting section 32 of the mating terminal 30 made of copper / copper alloy can be directly connected to the copper wire, thereby realizing the connection between the copper wire and the aluminum wire, and the plug-in end 20 of the plug-in terminal made of copper / copper alloy is directly connected to the contact section 31 of the copper / copper alloy of the mating terminal 30.

[0149] In some embodiments, as shown in Figure 11, a positioning hole 51 is provided at the front end of the mating terminal 30, and a positioning pin 52 is provided in the expansion and contraction insertion hole 223 of the plug-in terminal. The positioning pin 52 is plugged into the positioning hole 51 of the mating terminal 30, so that the longer mating terminal 30 can be positioned in the plug-in terminal, so that the front end of the mating terminal 30 will not shake in the expansion and contraction insertion hole of the plug-in terminal due to vibration, that is, the contact resistance change caused by shaking is prevented, and the current stability of the plug-in structure is maintained; it can also avoid the mating terminal 30 from shaking too much, which may cause the cables connected at the rear end to contact each other and cause a short circuit, thereby reducing the chance of short circuit accidents and electric shock casualties.

[0150] In some embodiments, as shown in FIG9 , each elastic sheet 222 extends in a corrugated shape in the longitudinal direction, and the outer wall surface of the mating terminal 30 extends in a corrugated shape in the axial direction to conform to the elastic sheet 222. By providing the elastic sheet 222 with a corrugated structure, the contact area between the elastic sheet 222 and the mating terminal 30 is increased, thereby enhancing the electrical performance of the plug-in terminal. In addition, the mating terminal 30 is axially positioned to prevent it from falling out of the expansion and contraction insertion hole, thereby improving safety and reliability.

[0151] In some embodiments, the outer diameter of the portion of the mating terminal inserted into the expansion and contraction insertion hole 223 is r1, and the minimum inner diameter of the expansion and contraction insertion hole 223 is r2. (r1-r2) / r1*100%=N, and 0.5%≤N≤20%. In other words, r1 is smaller than r2. This allows the expansion and contraction insertion hole 223 to more firmly grip the mating terminal due to the tension of the metal after insertion.

[0152] In order to test the effect of N value on the gripping force and contact resistance between terminals, the inventors selected ten groups of terminals with different N values ​​for testing. The test results are shown in Table 7.

[0153] The method for testing the gripping force of the plug-in terminal is as follows: use a thin-film piezoelectric dynamometer, attached to the mating terminal 30, so that the outer diameter of the mating terminal 30 to which the thin-film piezoelectric dynamometer is attached = r1, the plug-in terminal and the mating terminal 30 are plugged together, and then the value on the thin-film piezoelectric dynamometer is read, which is the gripping force of the plug-in terminal. In this embodiment, a gripping force less than 30N is an ideal value.

[0154] The test method for the contact resistance of the plug-in terminal is: use a micro-resistance meter to measure the resistance at the contact position between the plug-in terminal and the mating terminal 30, and read the value on the micro-resistance meter, which is the contact resistance between the plug-in terminal and the mating terminal 30. In this embodiment, the contact resistance is less than 50μΩ, which is an ideal value.

[0155] Table 7: Effect of different N values ​​on the gripping force and contact resistance of plug terminals

[0156]

[0157] As can be seen from Table 7, when the value of N is less than 0.5%, the gripping force between the terminals is too small, which is less than the ideal value requirement, which easily causes the terminals to be loosely plugged in, and the contact resistance between the terminals is too large, exceeding the ideal value requirement, which will cause the temperature rise of the plug-in connection mechanism to be too high, reducing the safety of the plug-in connection mechanism and shortening the service life of the electrical device. When the value of N is greater than 20%, since the inner diameter of the expansion and contraction insertion hole 223 is too different from the outer diameter of the mating terminal 30, the mating terminal 30 cannot be inserted and normal electrical conduction cannot be performed. Therefore, the inventors selected a value range of N between 0.5% and 20%, which not only ensures that the plug-in terminal is relatively easy to insert into the mating terminal 30, but also ensures that the gripping force and contact resistance between the plug-in terminal and the mating terminal 30 meet the ideal value requirements, greatly ensuring the mechanical and electrical properties of the plug-in connection mechanism and extending the service life of the electrical device.

[0158] When the inner diameter of the expansion and contraction insertion hole 223 is uneven, for example, the inner hole cross-sectional area of ​​the expansion and contraction insertion hole 223 on the side close to the fixing unit 21 is larger than the inner hole cross-sectional area at the open end of the elastic unit 22, r2 is the minimum inner diameter of the expansion and contraction insertion hole 223.

[0159] An embodiment of a third aspect of the present application provides a plug-in terminal assembly, comprising the plug-in terminal according to the embodiment of the first aspect and a temperature sensor provided on the plug-in terminal.

[0160] The plug terminal is provided with a through hole 60, as shown in FIG10 , a temperature sensor is provided in the through hole 60. The temperature sensor can be installed at any through hole of the terminal, and the temperature sensor can be installed in three directions, XYZ.

[0161] This solution makes the temperature measurement accuracy close to or equal to the theoretical absolute value, with extremely high detection accuracy and fast output capability

[0162] The temperature sensor is partially or entirely disposed in the through hole 60 .

[0163] The temperature sensor is interference-fitted with the through hole 60 .

[0164] The outer wall of the temperature sensor is provided with an external thread, the through hole 60 is provided with an internal thread, and the temperature sensor is threadedly connected to the through hole 60. The temperature sensor can be installed and then connected to the transmission cable.

[0165] The temperature sensor is provided with a shielding layer outside, which can shield the interference of the external magnetic field on the temperature sensor, ensure that the signal transmitted by the temperature sensor is stable and not distorted, and ensure the accuracy of the data.

[0166] The temperature sensor is either an NTC or PTC temperature sensor. These sensors are compact and can measure gaps that other thermometers cannot. They are easy to use, with resistance values ​​​​selectable between 0.1 and 100 kΩ. They are easily processed into complex shapes and can be mass-produced. They offer excellent stability and a strong overload capacity, making them suitable for applications such as adapters, which require compact size and stable performance.

[0167] The through hole 60 is provided on the fixing unit 21 .

[0168] In some embodiments, a temperature acquisition device is provided: the output module includes a programmable controller, a transmission unit and a power supply, the temperature sensor is electrically connected to the programmable controller, and the transmission unit sends the temperature information obtained by the programmable controller wirelessly (or wired).

[0169] Furthermore, some embodiments provide a temperature collection system: a collection terminal obtains temperature information via an information receiving device, a storage unit is used to store the temperature information, and a comparison unit is used to compare the temperature information with a preset safety level. If the collected information exceeds the preset level, the collection terminal issues an alarm via an alarm unit to notify staff. Multiple collection terminals are remotely connected to a server, which monitors all collected temperature information and can also transmit the temperature information to a mobile terminal, allowing staff to monitor the temperature of each terminal in the work area at any time and anywhere.

[0170] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A plug-in terminal, characterized in that, include: Connection ends and plug-in ends; The plug-in end includes a fixing unit and an elastic unit, wherein the fixing unit is used to be mounted on the coupling device; One end of the connection terminal can be electrically connected to a cable, and the other end of the connection terminal is connected to the fixing unit; The elastic unit is provided with an expansion and contraction insertion hole for interlocking with the mating terminal and for electrical connection with the mating terminal.

2. The plug-in terminal according to claim 1, characterized in that, The connecting end is made of aluminum or aluminum alloy, and the plug-in end is made of copper or copper alloy.

3. The plug-in terminal according to claim 2, characterized in that, The connecting end and the fixing unit are connected together by one or more of the following methods: friction welding, ultrasonic welding, arc welding, laser welding, and resistance welding.

4. The plug-in terminal according to claim 1, characterized in that, The elastic unit includes a copper segment and an aluminum segment. One end of the aluminum segment is fixedly connected to the copper segment, and the other end is connected to the fixed unit.

5. The plug-in terminal according to claim 4, characterized in that, The length of the copper segment accounts for 0.5% to 99.9% of the total length of the elastic unit.

6. The plug-in terminal according to claim 1, characterized in that, The elastic unit includes an expansion joint extending in the longitudinal direction of the plug terminal, the expansion joint dividing the elastic unit into elastic sheets.

7. The plug-in terminal according to claim 6, characterized in that, Each of the elastic sheets extends in a corrugated shape along its length.

8. The plug-in terminal according to claim 6, characterized in that, The width of the expansion joint on the side near the fixed unit is greater than or equal to the width on the side of the opening of the elastic unit.

9. The plug-in terminal according to claim 6, characterized in that, The minimum width of the expansion joint ranges from 0.01mm to 12mm.

10. The plug-in terminal according to claim 9, characterized in that, The minimum width of the expansion joint is 0.1mm-10mm.

11. The plug-in terminal according to claim 6, characterized in that, The number of elastic sheets is 4, 6, 8, 10, 12, 14, or 16.

12. The plug-in terminal according to claim 6, characterized in that, The thickness of the elastic sheet on the opening side of the elastic unit is greater than the thickness on the side closer to the fixing unit.

13. The plug-in terminal according to claim 1, characterized in that, The expansion and contraction insertion hole of the elastic unit has an inner hole cross-sectional area on the side near the fixed unit that is larger than the inner hole cross-sectional area on the opening side of the elastic unit.

14. The plug-in terminal according to claim 1, characterized in that, The expansion and contraction insertion hole is provided with a positioning pin, which is used to interlock with the positioning hole at the front end of the mating terminal.

15. The plug-in terminal according to claim 14, characterized in that, The positioning pin is arranged axially along the expansion and contraction insertion hole and is fixed on the end wall of the expansion and contraction insertion hole. The positioning pin has a top and a bottom connected to the end wall, and the cross-sectional area of ​​the top is less than or equal to the cross-sectional area of ​​the bottom.

16. The plug-in terminal according to claim 1, characterized in that, The inner cross-sectional shape of the expansion and contraction insertion hole of the elastic unit is circular, elliptical, polygonal, flat, E-shaped, F-shaped, H-shaped, K-shaped, L-shaped, T-shaped, U-shaped, V-shaped, W-shaped, X-shaped, Y-shaped, Z-shaped, semi-arc, arc-shaped, or wavy.

17. The plug-in terminal according to claim 1, characterized in that, The opening side of the elastic unit is provided with a chamfer or rounding.

18. The plug-in terminal according to claim 1, characterized in that, The outer side of the elastic unit has a circumferentially arranged groove, which corresponds to the expansion and contraction insertion hole. The plug-in terminal also includes an elastic sleeve for fitting onto the groove.

19. The plug-in terminal according to claim 1, characterized in that, The connecting end and the plug end are integrally formed.

20. The plug-in terminal according to claim 1, characterized in that, The connecting end and the plug end are connected by crimping, snap-fitting, threaded connection, welding, riveting or embedded connection.

21. The plug-in terminal according to claim 1, characterized in that, The connecting end has a flat plate structure, a U-shaped structure, an arc-shaped structure, a cylindrical structure, a bowl-shaped structure, or a polygonal structure.

22. The plug-in terminal according to any one of claims 1 to 21, characterized in that, The material of the connecting end and / or the plug end contains tellurium.

23. The plug-in terminal according to claim 22, characterized in that, The tellurium content in the material of the connecting end and / or the plug end is 0.1%-5%.

24. The plug-in terminal according to any one of claims 1-21, characterized in that, The connecting end and / or the plug end have a plating.

25. The plug-in terminal according to claim 24, characterized in that, The plating thickness on the connecting end and / or the plug end is consistent.

26. The plug-in terminal according to claim 24, characterized in that, The material of the plating on the connecting end is different from the material of the plating on the plug end.

27. The plug-in terminal according to claim 24, characterized in that, The coating material is one or more of the following: gold, silver, nickel, tin, zinc, tin-lead alloy, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy.

28. The plug-in terminal according to claim 24, characterized in that, The coating includes a base layer and a surface layer.

29. The plug-in terminal according to claim 28, characterized in that, The bottom layer material is one or more of gold, silver, nickel, tin, tin-lead alloy, and zinc; the surface layer material is one or more of gold, silver, nickel, tin, tin-lead alloy, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy.

30. The plug-in terminal according to claim 28, characterized in that, The thickness of the bottom layer is 0.01μm-15μm.

31. The plug-in terminal according to claim 28, characterized in that, The thickness of the bottom layer is 0.1μm-9μm.

32. The plug-in terminal according to claim 28, characterized in that, The thickness of the surface layer is 0.5μm-55μm.

33. The plug-in terminal according to claim 28, characterized in that, The thickness of the surface layer is 1μm-35μm.

34. A plug-in connection structure, characterized in that, The mating connection structure includes mating terminals and plug-in terminals as described in any one of claims 1 to 33, wherein the mating terminals are inserted into the expansion-retraction insertion hole, and the outer sidewall of the mating terminals is tightly fitted with the inner sidewall of the elastic unit.

35. The interlocking connection structure according to claim 34, characterized in that, The connecting end is made of aluminum or aluminum alloy, and the plug-in end is made of copper or copper alloy; the mating terminal includes a contact section and a connecting section connected to each other. The contact section is made of copper or copper alloy, and the connecting section is made of aluminum or aluminum alloy. The contact section is inserted into the expansion and contraction insertion hole, and the outer wall of the contact section is tightly fitted with the inner wall of the elastic unit. The connecting section is located outside the expansion and contraction insertion hole.

36. The interlocking connection structure according to claim 35, characterized in that, The contact section and the connecting section are connected together by one or more of the following methods: friction welding, ultrasonic welding, arc welding, laser welding, and resistance welding.

37. The interlocking connection structure according to claim 34, characterized in that, The connecting end is made of aluminum or aluminum alloy, and the plug-in end is made of copper or copper alloy. The mating terminal includes a contact section and a connecting section connected to each other. The mating terminal is made of copper or copper alloy. The contact section is inserted into the expansion and contraction insertion hole. The outer wall of the contact section is tightly fitted with the inner wall of the elastic unit. The connecting section is located outside the expansion and contraction insertion hole.

38. The interlocking connection structure according to claim 34, characterized in that, The mating terminal has a positioning hole at its front end, and the plug-in terminal has a positioning pin in its expansion and contraction insertion hole. The positioning pin is interlocked with the positioning hole of the mating terminal.

39. The interlocking connection structure according to claim 34, characterized in that, The elastic unit includes an expansion joint extending in the longitudinal direction of the plug terminal, the expansion joint dividing the elastic unit into elastic sheets, the elastic sheets extending in a corrugated shape in the length direction, the outer wall surface of the mating terminal extending in a corrugated shape in the axial direction, and the outer wall surface of the mating terminal fitting against the elastic sheets.

40. The interlocking connection structure according to claim 34, characterized in that, The outer diameter of the portion of the mating terminal inserted into the expansion and contraction insertion hole is r1, the minimum inner diameter of the expansion and contraction insertion hole is r2, (r1-r2) / r1*100%=N, and 0.5%≤N≤20%.

41. A plug-in terminal assembly, characterized in that, It includes the plug-in terminal as described in any one of claims 1 to 33 and a temperature sensor disposed on the plug-in terminal.

42. The plug-in terminal assembly according to claim 41, characterized in that... The plug-in terminal is provided with a through hole, and the temperature sensor is partially or entirely disposed in the through hole.

43. The plug-in terminal assembly according to claim 42, characterized in that, The temperature sensor is interference-fitted with the through hole.

44. The plug-in terminal assembly according to claim 42, characterized in that, The outer wall of the temperature sensor is provided with an external thread, the through hole is provided with an internal thread, and the temperature sensor is threadedly connected to the through hole.

45. The plug-in terminal assembly according to claim 41, characterized in that, The temperature sensor is equipped with a shielding layer on the outside.

46. ​​The plug-in terminal assembly according to claim 41, characterized in that... The temperature sensor is an NTC temperature sensor or a PTC temperature sensor.

47. The plug-in terminal assembly according to claim 41, characterized in that... The temperature sensor is mounted on the fixed unit.

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