plug

Abstract

The invention relates to a plug, comprising a connecting element and an elastic element which are arranged and connected together along the axial direction of the plug. The elastic element comprises several elastic plates arranged at intervals along the circumference of the plug. One end of the elastic plate is away from the connecting element, forming the free end of the elastic element. Several elastic plates surround the opening to receive the mating end inserted from the free end. The plug also comprises conductive wear-resistant layers located in the opening and correspondingly fixed to the inner walls of the elastic plates. The conductive wear-resistant layers protrude from the inner wall surfaces of the elastic plates in a corresponding manner to contact the outer wall of the mating end. In the invention, the conductive wear-resistant layers are provided to, on the one hand, provide wear resistance and prevent the inner wall of the elastic plate from wearing out and extend the life of the plug, and on the other hand, provide electrical conductivity by electrically connecting the elastic plate to the mating end.

Description

A plug-in terminal

[0001] Related applications

[0002] This application claims priority to the Chinese invention patent application with application number 202110803170.3 filed on July 15, 2021, and the Chinese utility model patent application with application number 202121611139.1 filed on July 15, 2021, and cites the contents disclosed in the above patent applications 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. Background Art

[0004] During use, the plug-in terminals need to be plugged into the mating terminals. Frequent plugging and unplugging actions will cause wear on the plug-in terminals, which will not only reduce the service life of the plug-in terminals, but also cause poor contact of the plug-in terminals, affecting normal use, and in serious cases, may cause safety accidents.

[0005] Summary of the Invention

[0006] The purpose of the present application is to provide an elastic plug-in terminal to solve the problem that the existing plug-in terminal is easily worn.

[0007] To achieve the above-mentioned purpose, the present application proposes a plug-in terminal, which includes a connecting unit and an elastic unit arranged and connected along the axial direction of the plug-in terminal; the elastic unit includes a plurality of elastic sheets arranged at intervals along the circumference of the plug-in terminal, and the ends of the plurality of elastic sheets away from the connecting unit constitute the free ends of the elastic unit, and the plurality of elastic sheets form a cavity for accommodating the mating terminal inserted from the free end; the plug-in terminal also includes a conductive wear-resistant layer located in the cavity and fixed on the inner wall of each of the elastic sheets, the conductive wear-resistant layer protrudes from the inner wall surface of the elastic sheet and can contact the outer wall of the mating terminal.

[0008] The features and advantages of the plug-in terminal of this application are:

[0009] 1. This application provides elasticity by providing an elastic sheet, enabling close contact with the mating terminal, ensuring a larger contact area and achieving better electrical and mechanical properties. The conductive wear-resistant layer provides a wear-resistant effect, preventing wear on the inner wall of the elastic sheet and extending the service life of the plug-in terminal. Furthermore, the elastic sheet is electrically connected to the mating terminal, providing electrical conductivity.

[0010] 2. This application provides multiple conductive wear-resistant layers on each elastic sheet. Each elastic sheet contacts the outer wall of the mating terminal through the multiple conductive wear-resistant layers, thereby increasing the contact area between the plug-in terminal and the mating terminal and improving wear resistance.

[0011] 3. This application provides scraping protrusions on the inner wall of each elastic sheet. When the mating terminal is inserted, the scraping protrusions first contact the mating terminal, removing debris on the mating terminal and preventing debris from being caught between the conductive wear-resistant layer and the mating terminal, thereby maintaining good electrical contact between the conductive wear-resistant layer and the mating terminal.

[0012] 4. This application provides arc-shaped grooves on the outer wall of each elastic sheet to eliminate external stress on the elastic sheet, allowing the elastic sheet to maintain good elasticity after continuous deformation and repeated temperature increases, making the elastic sheet less likely to deform;

[0013] 5. This application increases the positive pressure after the elastic sheet and the mating terminal are plugged in by arranging spiral protrusions and / or multiple protrusions on the inner wall surface of each elastic sheet, thereby effectively reducing the contact resistance and reducing the risk of fire caused by temperature rise. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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:

[0015] FIG1 is a schematic diagram of the external structure of a plug terminal according to a first embodiment of the present application;

[0016] FIG2 is a cross-sectional view of the plug terminal of FIG1 ;

[0017] FIG3 is a cross-sectional view of a plug terminal according to a second embodiment of the present application;

[0018] FIG4 is a cross-sectional view of a plug terminal according to a third embodiment of the present application;

[0019] FIG5 is a cross-sectional view of a plug terminal according to a fourth embodiment of the present application. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0021] In the description of this application, unless otherwise specified, "plurality" means two or more. In the description of this application, unless otherwise specified, the term "connection" should be understood broadly, for example, to mean a fixed connection, a detachable connection, a direct connection, or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this patent based on the specific circumstances.

[0022] As shown in Figures 1 and 2, the present application provides a plug-in terminal, which includes a connecting unit 1 and an elastic unit 2 arranged and connected along the axial direction of the plug-in terminal. The elastic unit 2 includes a plurality of elastic sheets 21 arranged at intervals along the circumference of the plug-in terminal. The ends of the plurality of elastic sheets 21 away from the connecting unit 1 constitute the free ends 22 of the elastic unit 2. The plurality of elastic sheets 21 form a cavity for receiving the mating terminal inserted from the free ends 22. The plug-in terminal also includes a conductive wear-resistant layer 3 located in the cavity and fixed on the inner wall of each elastic sheet 21. The conductive wear-resistant layer 3 protrudes from the inner wall surface 211 of the elastic sheet 21 and can contact the outer wall of the mating terminal.

[0023] The present application provides an elastic sheet 21 so that the elastic unit 2 has elasticity and can be in close contact with the mating terminal, thereby ensuring a larger contact area and achieving better electrical and mechanical properties. By providing a conductive wear-resistant layer 3, on the one hand, it has a wear-resistant effect, preventing the inner wall of the elastic sheet 21 from being worn, thereby extending the service life of the plug-in terminal. On the other hand, it electrically connects the elastic sheet 21 to the mating terminal, thereby playing a conductive role.

[0024] As shown in Figure 2, in one embodiment, the conductive wear-resistant layers 3 on the multiple elastic sheets 21 correspond in sequence in the circumferential direction of the plug-in terminal, that is, the conductive wear-resistant layers 3 on the multiple elastic sheets 21 constitute a wear-resistant ring extending discontinuously along the circumference of the plug-in terminal, and the conductive wear-resistant layer 3 is arranged adjacent to the free end 22 to prevent the mating terminal from rubbing against the free end of the elastic sheet 21 when the mating terminal is inserted into the cavity.

[0025] Furthermore, both axial ends of the conductive wear-resistant layer 3 are chamfered or rounded to facilitate insertion of the mating terminal.

[0026] As shown in FIG5 , in one embodiment, each elastic sheet 21 is provided with a plurality of conductive wear-resistant layers 3 spaced apart along its length direction. Each elastic sheet 21 contacts the outer wall of the mating terminal through the plurality of conductive wear-resistant layers 3 , thereby increasing the contact area between the plug-in terminal and the mating terminal and improving the wear resistance.

[0027] In one embodiment, as shown in Figure 2, the conductive wear-resistant layer 3 protrudes as a whole from the inner wall surface 211 of the elastic sheet 21, that is, the inner wall surface of the elastic sheet 21 is smooth, and the conductive wear-resistant layer 3 is fixed on the inner wall surface of the elastic sheet 21. The overall protruding height of the conductive wear-resistant layer 3 is 0.5μm-70μm.

[0028] In another embodiment, as shown in Figure 3, the inner wall surface 211 of each elastic sheet 21 is respectively provided with an embedding groove 212, a portion of the conductive wear-resistant layer 3 is fixedly embedded in the embedding groove 212, and another portion of the conductive wear-resistant layer 3 protrudes from the inner wall surface 211 of the elastic sheet 21, and the overall protruding height of the conductive wear-resistant layer 3 is 0.5μm-70μm.

[0029] However, the present application is not limited thereto, and the conductive wear-resistant layer 3 may also be fixed to the inner wall surface of the elastic sheet 21 by other means.

[0030] In order to test the effect of the overall protrusion height of the conductive wear-resistant layer 3 on the wear and conductivity of the conductive wear-resistant layer 3, the inventor selected ten groups of terminal groups with different protrusion heights for testing, and tested the number of plugging and unplugging times and the conductivity when the conductive wear-resistant layer 3 was worn. The test results are shown in Table 1.

[0031] The plugging and unplugging times reported in Table 1 below were measured by fixing the plug terminals on a test bench and using a mechanical device to simulate plugging and unplugging the plug terminals with their counterparts. After every 100 plugging and unplugging cycles, the test was stopped to observe damage to the conductive wear-resistant layer 3 of the terminals. When scratches appeared on the conductive wear-resistant layer 3, exposing the terminal material, the test was stopped and the plugging and unplugging times at that time were recorded. In this embodiment, plugging and unplugging times less than 8,000 cycles were considered unacceptable.

[0032] The conductivity in Table 1 below is obtained by plugging the plug-in terminal into the mating terminal, passing current through the mating terminal structure, and testing the conductivity of the corresponding terminal mating point. In this embodiment, a conductivity greater than 99% is considered acceptable.

[0033] The test results are shown in Table 1.

[0034] Table 1: Effects of different protruding heights of the conductive wear-resistant layer 3 on the plug-in and plug-out times and conductivity of the plug-in terminal

[0035]

[0036] As can be seen from Table 1, when the height of the conductive wear-resistant layer 3 of the terminal is less than 0.5μm, the conductivity between the terminals is all qualified, but the number of plug-in and unplugging times of the plug-in terminal does not meet the requirements, that is, the conductive wear-resistant layer 3 of the terminal is easily worn and cannot meet the service life requirements of the plug-in terminal. When the height of the conductive wear-resistant layer 3 of the terminal is greater than 70μm, although the number of plug-in and unplugging times of the plug-in terminal is qualified, the height of the conductive wear-resistant layer 3 of the terminal is too high, which increases the contact resistance, so the conductivity between the terminals does not meet the requirements, and the electrical performance of the terminal-to-plug structure is poor. Therefore, the inventors selected a value range of the protrusion height between 0.5μm-70μm, which can meet both the plug-in and unplugging times requirements of the plug-in terminal and the conductivity of the plug-in terminal. This greatly guarantees the electrical performance of the plug-in connection mechanism and extends the service life of the electrical device.

[0037] In one embodiment, the inner surface 31 of the conductive wear-resistant layer 3 is an arc surface that can fit with the outer wall surface of the mating terminal to increase the contact area between the conductive wear-resistant layer and the mating terminal. The cross-sections of the plug-in terminal and the mating terminal are generally circular. During the use of the plug-in terminal, if the inner wall of the plug-in terminal cannot completely fit with the outer wall surface of the mating terminal, it will cause poor contact of the plug-in terminal, increase the contact resistance, and further may cause the plug-in terminal to overheat during operation and catch fire. In the present application, the inner surface 31 of the conductive wear-resistant layer 3 is set to an arc surface that can fit with the outer wall surface of the mating terminal, increasing the contact area between the conductive wear-resistant layer and the mating terminal, effectively reducing the contact resistance, and thereby reducing the risk of fire caused by increased temperature.

[0038] In order to increase the contact area between the elastic piece 21 and the mating terminal, there are the following three embodiments.

[0039] In the first embodiment, a spiral protrusion for contacting the mating terminal is provided on the inner wall surface 211 of the elastic sheet 21. The spiral protrusion can increase the positive pressure after plugging with the mating terminal, thereby effectively reducing the contact resistance and reducing the risk of fire caused by temperature rise.

[0040] In the second embodiment, a plurality of protrusions for contacting the mating terminals are provided on the inner wall surface 211 of the elastic sheet 21. The protrusions can increase the positive pressure after plugging with the mating terminals, thereby effectively reducing the contact resistance and reducing the risk of fire caused by temperature rise.

[0041] In the third embodiment, a spiral protrusion and a plurality of protrusions for contacting the mating terminal are provided on the inner wall surface 211 of the elastic sheet 21. The provision of the spiral protrusion and the plurality of protrusions at the same time can further increase the contact area between the elastic sheet 21 and the mating terminal, further increase the positive pressure after plugging with the mating terminal, and thereby effectively reduce the contact resistance and reduce the risk of fire caused by temperature rise.

[0042] In one embodiment, the conductive wear-resistant layer 3 includes a bottom layer and a surface layer, wherein the bottom layer is made of one or more of gold, silver, nickel, tin, tin-lead alloy and zinc; the surface layer is made of 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.

[0043] The conductive wear-resistant layer 3 is made of 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. As metal contacts that are frequently plugged in and out, the conductive wear-resistant layer 3 requires a highly wear-resistant metal to significantly extend the lifespan of the contacts. Furthermore, contacts require excellent electrical conductivity. The conductivity and stability of these metals are superior to those of copper or copper alloys, resulting in better electrical performance and a longer lifespan for the plug-in terminals.

[0044] To demonstrate the impact of different conductive wear-resistant layer (3) materials on the overall performance of plug-in terminals, the inventors used plug-in terminal samples of the same specifications and materials, but with different conductive wear-resistant layer (3) materials, and conducted a series of plug-in and pull-out cycle and corrosion resistance tests using matching connectors of the same specifications. The experimental results are shown in Table 2 below.

[0045] The plugging and unplugging times reported in Table 2 below were simulated by fixing the mating terminals on a test bench and mechanically inserting and unplugging them. After every 100 plugging and unplugging cycles, the test was stopped to observe damage to the conductive wear-resistant layer 3 on the terminal surface. If scratches appeared on the conductive wear-resistant layer 3, exposing the terminal material, the test was stopped and the plugging and unplugging times recorded. In this example, plugging and unplugging times less than 8,000 cycles were considered unacceptable.

[0046] The conductivity in Table 2 below is obtained by plugging the plug-in terminal into the mating terminal, passing current through the mating terminal structure, and testing the conductivity of the corresponding terminal mating point. In this embodiment, a conductivity greater than 99% is considered acceptable.

[0047] Table 2: Effects of different conductive wear-resistant layer 3 materials on the plug-in and plug-out times and conductivity of plug-in terminals

[0048]

[0049] As can be seen from Table 2 above, when the conductive wear-resistant layer 3 is made of gold, silver, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy, the experimental results exceed the standard value by a large margin, and the performance is relatively stable. When the conductive wear-resistant layer 3 is made of nickel, tin, tin-lead alloy, and zinc, the experimental results can also meet the requirements. Therefore, the inventors select the conductive wear-resistant layer 3 to be made of one or more combinations of gold, silver, nickel, tin, tin-lead alloy, zinc, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy.

[0050] The thickness of the conductive wear-resistant layer significantly impacts the overall performance and lifespan of the plug-in terminal. In severe cases, it can lead to a drastic reduction in product lifespan or even failure. If the conductive wear-resistant layer is too thin, the plug-in terminal's wear resistance will not meet the required standards. If the conductive wear-resistant layer is too thick, it will easily fall off the terminal surface, causing a decrease in wear resistance. This reduces the contact area between the plug-in terminal and the mating terminal, increases contact resistance, and can lead to risks such as fires caused by elevated temperatures. Furthermore, the conductive wear-resistant layer 3 is made of relatively expensive metal. Using a thicker conductive wear-resistant layer 3 does not improve performance and is therefore unsuitable for use.

[0051] In order to demonstrate the effect of thickness variation of the underlying conductive wear-resistant layer 3 on the overall performance of the plug-in terminal, the inventors used plug-in terminal samples of the same specifications and materials, with different nickel bottom layer thicknesses and the same silver surface layer thickness, and used mating connectors of the same specifications to conduct a series of temperature rise tests and plug-in and pull-out cycle tests. The experimental results are shown in Table 3 below.

[0052] The temperature rise test in Table 3 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.

[0053] The plugging and unplugging times reported in Table 3 below were simulated by fixing the mating terminals on a test bench and mechanically inserting and unplugging them. After every 100 plugging and unplugging cycles, the test was stopped to observe damage to the conductive wear-resistant layer 3 on the terminal surface. If scratches appeared on the conductive wear-resistant layer 3, exposing the terminal material, the test was stopped and the plugging and unplugging times recorded. In this example, plugging and unplugging times less than 8,000 cycles were considered unacceptable.

[0054] Table 3: Effects of different bottom conductive wear-resistant layer thicknesses on terminal temperature rise and plug-in and pull-out cycles

[0055]

[0056] As can be seen from Table 3 above, when the thickness of the underlying nickel layer is less than 0.01 μm, the temperature rise of the plug-in terminal is qualified, but because the conductive wear-resistant layer is too thin, the number of plug-in and plug-out cycles of the plug-in terminal is less than the qualified value, which does not meet the performance requirements of the plug-in terminal. This has a significant impact on the overall performance and lifespan of the docking plug, and in severe cases, it can cause a sudden reduction in product lifespan or even failure and combustion accidents. When the thickness of the underlying nickel layer is greater than 15 μm, due to the thick underlying conductive wear-resistant layer 3, the heat generated by the plug-in terminal cannot be dissipated, causing the temperature rise of the plug-in terminal to fail. Moreover, the thicker the underlying layer is, the more likely it is to fall off from the terminal surface, resulting in a decrease in the number of corrosion resistance cycles. Therefore, the inventors selected a thickness of 0.01 μm to 15 μm for the underlying conductive wear-resistant layer 3. Preferably, the inventors found that when the thickness of the underlying conductive wear-resistant layer 3 is 0.1 μm to 9 μm, the combined effect of the temperature rise and plug-in cycle of the plug-in terminal is better. Therefore, in order to further improve the safety, reliability and practicality of the product itself, the thickness of the underlying conductive wear-resistant layer 3 is preferably 0.1 μm to 9 μm.

[0057] In order to demonstrate the effect of thickness variation of the conductive wear-resistant surface layer 3 on the overall performance of the plug-in terminal, the inventors used plug-in terminal samples of the same specifications and materials, with the same nickel base layer thickness and different silver surface layer thicknesses, and used mating connectors of the same specifications to conduct a series of temperature rise and plug-in and pull-out cycle tests. The experimental results are shown in Table 4 below.

[0058] The experimental method is the same as the above experimental method.

[0059] Table 4: Effects of different thicknesses of the conductive wear-resistant layer 3 on temperature rise and plug-in cycles

[0060]

[0061] As can be seen from Table 4 above, when the thickness of the surface silver layer is less than 0.5 μm, although the temperature rise of the plug-in terminal is qualified, the number of plug-in and plug-out times of the plug-in terminal is less than the qualified value because the conductive wear-resistant layer 3 is too thin, 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 serious cases, it causes a sudden reduction in product life or even failure and combustion accidents. When the thickness of the surface silver layer is greater than 55 μm, due to the thicker underlying conductive wear-resistant layer 3, the heat generated by the plug-in terminal cannot be dissipated, making the temperature rise of the plug-in terminal unqualified. Moreover, the thicker conductive wear-resistant layer 3 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 metal of the surface conductive wear-resistant layer 3 is more expensive, using a thicker conductive wear-resistant layer 3 does not improve performance and has no use value. Therefore, the inventor selected the thickness of the surface conductive wear-resistant layer 3 to be 0.1 μm-55 μm.

[0062] Preferably, the inventors found that when the thickness of the surface conductive wear-resistant layer 3 is 1μm-35μm, the comprehensive effect of the temperature rise and the number of plugging and unplugging times of the plug terminal is better. Therefore, in order to further improve the safety, reliability and practicality of the product itself, the thickness of the surface conductive wear-resistant layer 3 is preferably 1μm-35μm.

[0063] In one embodiment, a plurality of conductive wear-resistant layers 3 are provided on the inner wall of the elastic sheet 21 and are arranged at intervals along the axial direction of the plug-in terminal. In this application, by providing a plurality of conductive wear-resistant layers on each elastic sheet, each elastic sheet contacts the outer wall of the mating terminal through the plurality of conductive wear-resistant layers, thereby increasing the contact area between the plug-in terminal and the mating terminal and improving the wear resistance.

[0064] In one embodiment, the inner diameter of the cavity of the plug-in terminal gradually decreases toward the free end 22, that is, the aperture of the cavity on the side of the free end 22 of the plug-in terminal is smallest, so that the mating terminal can be inserted into the cavity and the elastic sheet has a larger deformation space, so that the elastic unit 2 has a greater gripping force after being plugged into the mating terminal.

[0065] As shown in Figures 1 to 4, in one embodiment, an expansion joint 23 is formed between any two adjacent elastic sheets 21, and the width of each expansion joint 23 gradually decreases toward the free end 22, that is, the width of the expansion joint 23 on the side of the free end 22 of the plug-in terminal is the smallest, thereby making the width of the front end of the elastic sheet 21 larger, and thus being able to provide a conductive wear-resistant layer 3 with a larger width, thereby increasing the contact area between the conductive wear-resistant layer 3 and the mating terminal. In addition, the width of the expansion joint 23 at the rear end of the elastic sheet 21 is larger, which has good sediment and water discharge performance.

[0066] In one embodiment, the number of elastic sheets 21 is an even number, so that the elastic sheets 21 are symmetrically arranged to ensure symmetrical stress after the elastic sheets 21 contact the mating terminals. For example, the number of elastic sheets 21 is 4, 6, 8, 10, 12, 14 or 16.

[0067] As shown in Figure 4, in one embodiment, the plug terminal further includes a scraping protrusion 4 located in the cavity and fixed on the inner wall of each elastic sheet 21. In the axial direction of the plug terminal, the scraping protrusion 4 is located between the conductive wear-resistant layer 3 and the free end 22. Therefore, when the mating terminal is inserted, the scraping protrusion 4 first contacts the mating terminal to remove debris on the mating terminal, preventing the debris on the mating terminal from being sandwiched between the conductive wear-resistant layer 3 and the mating terminal, so that the conductive wear-resistant layer 3 maintains good electrical contact with the plug terminal.

[0068] In a feasible technical solution, the inner surface 41 of the scraping protrusion 4 does not protrude from the inner surface 31 of the conductive wear-resistant layer 3 to prevent the scraping protrusion 4 from interfering with the contact between the conductive wear-resistant layer 3 and the mating terminal.

[0069] In another feasible technical solution, the inner surface 41 of the scraping protrusions 4 on the multiple elastic sheets 21 and the inner surface 31 of the conductive wear-resistant layer 3 are both located on the same annular surface or the same conical surface. The scraping protrusions 4 will neither hinder the contact between the conductive wear-resistant layer and the mating terminal, nor can they support the mating terminal.

[0070] Furthermore, the scraping protrusion 4 is provided with a chamfer or a rounded corner on one side close to the free end 22 to facilitate the insertion of the mating terminal.

[0071] As shown in Figure 4, in one embodiment, an arc-shaped groove 213 is respectively provided on the outer wall of one end of each elastic sheet 21 close to the connecting unit 1. The arc-shaped grooves 213 on the multiple elastic sheets 21 constitute a discontinuous annular groove along the circumference of the plug-in terminal. By providing the arc-shaped grooves 213, the external stress of the elastic sheet 21 can be eliminated, so that the elastic sheet 21 maintains good elastic force after continuous deformation and repeated temperature increases, making the elastic sheet 21 not easily deformed.

[0072] Furthermore, the depth of the arc-shaped groove 213 is no more than one-third of the thickness of the elastic sheet 21 , which can eliminate the external stress of the elastic sheet 21 and prevent the elastic sheet 21 from being insufficient in strength due to being too thin.

[0073] In one embodiment, the connecting unit 1 is made of aluminum or aluminum alloy to connect aluminum wires or other aluminum conductors.

[0074] In one embodiment, the elastic unit 2 is made of copper or copper alloy to facilitate connection with copper wires or other copper conductors.

[0075] Due to the high voltage and current in electric vehicle cables, large-diameter copper conductors are required for current transmission. However, with rising copper prices, the material cost of copper conductors is increasing. Therefore, the search for alternatives to copper metal has begun to reduce costs. 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.

[0076] 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.

[0077] In order to solve the problem of difficulty in reliably connecting copper and aluminum wires in the prior art, in some embodiments, the material of the connecting unit 1 is aluminum or aluminum alloy, and the material of the elastic unit 2 is copper or copper alloy, thereby achieving reliable connection of the copper and aluminum wires, solving the problem of difficulty in reliably connecting the copper and aluminum wires.

[0078] Furthermore, the connection unit 1 and the elastic unit 2 are connected together by friction welding, ultrasonic welding, arc welding, laser welding, resistance welding or several other methods.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] Laser welding is an efficient and precise welding method that uses a high-energy-density laser beam as a heat source.

[0083] 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.

[0084] By adopting the above processing methods or combinations, the elastic unit 2 made of copper / copper alloy and the connecting unit 1 made of aluminum / aluminum alloy can be effectively connected, ensuring that the plug-in terminal has good mechanical and electrical properties.

[0085] 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, wherein, the plug-in terminal includes a connection unit (1) and an elastic unit (2) which are arranged along the axial direction of the plug-in terminal and connected; the elastic unit (2) includes a plurality of elastic pieces (21) arranged at intervals along the circumferential direction of the plug-in terminal, one ends of the plurality of elastic pieces (21) far away from the connection unit (1) form a free end (22) of the elastic unit (2), and the plurality of elastic pieces (21) enclose a cavity for receiving a mating terminal inserted from the free end (22); the plug-in terminal further includes a conductive wear-resistant layer (3) located in the cavity and fixed on the inner wall surfaces of the respective elastic pieces (21), the conductive wear-resistant layer (3) protrudes from the inner wall surface (211) of the elastic piece (21), and can contact the outer wall of the mating terminal.

2. The plug-in terminal according to claim 1, wherein, the conductive wear-resistant layers (3) on the plurality of elastic pieces (21) correspond to each other in sequence in the circumferential direction of the plug-in terminal, and the conductive wear-resistant layer (3) is arranged adjacent to the free end (22).

3. The plug-in terminal according to claim 1, wherein, the conductive wear-resistant layer (3) protrudes integrally from the inner wall surface (211) of the elastic piece (21), or, respectively concave grooves (212) are provided on the inner wall surfaces (211) of the respective elastic pieces (21), a part of the conductive wear-resistant layer (3) is located in the groove (212), and another part protrudes from the inner wall surface (211) of the elastic piece (21).

4. The plug-in terminal according to claim 3, wherein, the overall protruding height of the conductive wear-resistant layer (3) is 0.5 μm - 70 μm.

5. The plug-in terminal according to claim 1, wherein, the inner surface (31) of the conductive wear-resistant layer (3) is an arc surface capable of fitting with the outer wall surface of the mating terminal.

6. The plug-in terminal according to claim 1, wherein, spiral protrusions for contacting the mating terminal are provided on the inner wall surface (211) of the elastic piece (21); and / or, a plurality of bumps for contacting the mating terminal are provided on the inner wall surface (211) of the elastic piece (21).

7. The plug-in terminal according to claim 1, wherein, the conductive wear-resistant layer (3) includes a bottom layer and a surface layer, the material of the bottom layer is one or more of gold, silver, nickel, tin, tin-lead alloy and zinc; the material of the surface layer 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.

8. The plug-in terminal according to claim 7, wherein, the thickness of the bottom layer is 0.01 μm - 15 μm.

9. The plug-in terminal according to claim 7, wherein, the thickness of the bottom layer is 0.1 μm - 9 μm.

10. The plug-in terminal according to claim 7, wherein, the thickness of the surface layer is 0.5 μm - 55 μm.

11. The plug-in terminal according to claim 7, wherein, the thickness of the bottom layer is 1 μm - 35 μm.

12. The plug-in terminal according to any one of claims 1 to 11, wherein, A plurality of conductive wear-resistant layers (3) arranged at intervals along the axial direction of the insertion terminal are provided on the inner wall of the elastic piece (21).

13. The insertion terminal according to any one of claims 1 to 11, wherein, the inner diameter of the cavity gradually decreases in the direction close to the free end (22).

14. The insertion terminal according to any one of claims 1 to 11, wherein, the insertion terminal further includes scraping protrusions (4) located in the cavity and fixed to the inner walls of the respective elastic pieces (21). In the axial direction of the insertion terminal, the scraping protrusions (4) are located between the conductive wear-resistant layers (3) and the free end (22).

15. The insertion terminal according to claim 14, wherein, the inner surface (41) of the scraping protrusion (4) does not protrude from the inner surface (31) of the conductive wear-resistant layer (3).

16. The insertion terminal according to claim 14, wherein, the inner surfaces (41) of the scraping protrusions (4) on the plurality of elastic pieces (21) and the inner surface (31) of the conductive wear-resistant layer (3) are all located on the same toroidal surface or the same conical surface.

17. The insertion terminal according to any one of claims 1 to 11, wherein, an arc-shaped groove (213) is provided on the outer wall of one end of the elastic piece (21) close to the connection unit (1).

18. The insertion terminal according to any one of claims 1 to 11, wherein, the connection unit (1) is made of aluminum or aluminum alloy.

19. The insertion terminal according to any one of claims 1 to 11, wherein, the elastic unit (2) is made of copper or copper alloy.

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