Terminal having memory ring

Abstract

A terminal having a memory ring. The terminal comprises a terminal body (1) and a memory ring (2). The terminal body (1) comprises a contact section (13). The memory ring (2) is sleeved outside the contact section (13), the memory ring (2) is in contact with the contact section (13), the material of the memory ring (2) is a memory alloy, and the memory ring (2) is capable of contracting the contact section (13). By means of the terminal having the memory ring, no-insertion-force docking can be achieved, and the contact area and the contact force between the terminal and a mating terminal are ensured by means of an increase in temperature during operation, thereby improving the reliability of contact. Since the requirement for an insertion force is omitted, the operation is easier, and the operation efficiency is improved.

Description

A terminal with a memory ring

[0001] Related applications

[0002] This application claims priority to the Chinese invention patent application with application number 202110801855.4 filed on July 15, 2021, and the Chinese utility model patent application with application number 202121611259.1 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 a terminal with a memory ring. Background Art

[0004] With the increasing popularity of electric vehicles, the market demand for charging plugs and charging stations is also increasing. In existing technologies, the terminals on charging plugs, charging piles, charging stations, and vehicles all rely on springs, bolts, and mechanical structures to achieve contact with their mating terminals. These require a certain amount of insertion force and tools to complete installation. Furthermore, during operation, the terminals' temperature rises, leading to increased resistance and decreased current flow.

[0005] Summary of the Invention

[0006] In order to improve the efficiency of terminal docking, the present application provides a terminal with a memory ring, which can achieve insertion force-free docking. During work, the contact area and contact force between the terminal and the mating terminal are guaranteed by increasing the temperature, thereby improving the contact reliability. Since the insertion force requirement is eliminated, the work is easier and the work efficiency is improved.

[0007] The technical solution adopted by this application to solve its technical problems is:

[0008] A terminal with a memory ring comprises a terminal body and a memory ring. The terminal body comprises a contact segment, an inserting cavity with a varying radial size is arranged inside the contact segment, the memory ring is sleeved outside the contact segment and contacts the contact segment, and the memory ring is made of a memory alloy.

[0009] The beneficial effects of this application are:

[0010] 1. Realize zero-insertion-force docking. During operation, the temperature rises to ensure the contact area and contact force between the terminal and the mating terminal, thereby improving the contact reliability. Since the insertion force requirement is eliminated, the work becomes easier and the work efficiency is improved.

[0011] 2. When the terminal is working, the temperature will gradually increase. When it exceeds the transformation temperature, the memory ring will shrink, thereby increasing the contact area between the terminal and the mating terminal, and the resistance will decrease, thereby preventing the current between the terminal and the mating terminal from further decreasing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and do not constitute a limitation of the present application. In the drawings:

[0013] FIG1 is a schematic diagram of the terminal with a memory ring in the expanded state described in the present application.

[0014] FIG2 is a schematic diagram of a terminal body.

[0015] FIG3 is a schematic diagram of a memory ring.

[0016] FIG4 is a schematic diagram of the terminal with the memory ring in the retracted state described in the present application.

[0017] FIG5 is a schematic diagram showing a case where the angle between the plugging direction of the contact section and the wiring direction of the cable connecting section is 90°.

[0018] FIG. 6 is a schematic diagram of the memory ring with its ends overlapping at the opening. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present application and their descriptions are used to explain the present application, but are not intended to limit the present application.

[0020] An embodiment of the present application provides a terminal with a memory ring, including a terminal body 1 and a memory ring 2. The terminal body 1 contains a contact segment 13, and a plug-in cavity with a varying radial size is provided inside the contact segment 13. The memory ring 2 is sleeved outside the contact segment 13 and contacts the contact segment 13. The material of the memory ring 2 is a memory alloy, and the memory ring 2 can cause the contact segment 13 to shrink, as shown in Figures 1 to 4.

[0021] The memory ring has a transition temperature, and contact segment 13 is typically in a radially expanded state. When the temperature of memory ring 2 falls below the transition temperature, it expands radially, causing contact segment 13 to expand simultaneously. When the temperature of memory ring 2 rises above the transition temperature, it contracts radially, causing contact segment 13 to contract simultaneously. This ensures the contact area and force between the terminal and the mating terminal through temperature increases, improving contact reliability. By eliminating the insertion force requirement, work becomes easier and efficiency is increased.

[0022] The material of the memory ring 2 is a memory alloy. Specifically, a memory alloy with a transformation temperature of 40°C-70°C can be selected as the material to make the memory ring 2. That is, the transformation temperature of the memory ring 2 is 40°C-70°C.

[0023] A memory alloy refers to a special metal material that undergoes plastic deformation within a certain temperature range and can restore its original macroscopic shape within another temperature range. In this application, the temperature point of this plastic deformation is called the transformation temperature. Changing the content of different metals in the memory alloy can change the transformation temperature of the memory alloy. Generally, the transformation temperature is selected between 40°C and 70°C. Because if the transformation temperature is lower than 40°C, when no current is conducted, the ambient temperature of the terminal will also reach close to 40°C. At this time, the memory ring 2 will be in a contracted state, the aperture of the terminal will become smaller, and the plug terminal will not be able to be inserted into the plug cavity in the contact section 13, which will cause the electrical device to be unable to be plugged in and unable to work.

[0024] At room temperature, the plug-in terminal and the terminal with the memory ring start to conduct electricity after being plugged in. Since the memory ring 2 is in an expanded state at the beginning of the plug-in, the contact area between the terminal with the memory shrink ring and the plug-in terminal is small, and the current is large, which causes the terminal to start heating up after plugging in. If the abnormal temperature is higher than 70°C, the terminal heating time is long, and the electrical device is in a high current state for a long time, which is easy to cause electrical aging. In severe cases, the electrical device may be overloaded and damaged, causing unnecessary losses.

[0025] Therefore, in general, the transformation temperature of the terminal with memory shrink ring is set between 40℃-70℃.

[0026] In this embodiment, the contact segment 13 is provided with at least two slots along the axial direction, which divide the contact segment into at least two contact springs. The contact segment 13 includes a plurality of contact springs 131, which are arranged at intervals along the circumference of the contact segment 13.

[0027] In some embodiments, the inscribed cross-section of the inner surface of the plug cavity 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 inscribed cross-section of the inner surface of the plug cavity can be designed in various shapes to facilitate designers to select different shapes of plug terminals based on the actual plug terminal layout environment, thereby reducing the volume of the plug structure, optimizing the contact area, and enhancing the electrical performance of the plug terminals.

[0028] The outer surface of the contact section 13 is provided with at least one mounting ring groove 14, and at least one memory ring 2 is matchedly sleeved outside each mounting ring groove 14. The cross section of the mounting ring groove 14 can be circular, polygonal, rectangular, diamond-shaped, triangular, fan-shaped or trapezoidal.

[0029] In this embodiment, one end of the contact segment 13 is connected to one end of the transition segment 12, and multiple memory rings 2, such as three, are sleeved outside the contact segment 13. The multiple memory rings 2 are arranged in sequence from one end of the contact segment 13 to the other end of the contact segment 13, as shown in Figure 5.

[0030] In this embodiment, the cross-sectional area of ​​the plurality of memory rings 2 may gradually increase or decrease along the direction from one end of the contact segment 13 to the other end of the contact segment 13. The distance between two adjacent memory rings 2 may gradually increase or decrease along the direction from one end of the contact segment 13 to the other end of the contact segment 13.

[0031] In this embodiment, the memory ring 2 is an open ring structure, meaning that it can form a line segment after stretching. The memory ring 2 is engaged with the contact segment 13 and includes an opening 21. The end surface 22 of the memory ring 2 at the opening 21 is arranged parallel to or inclined relative to the axis L1 of the memory ring 2. The length of the opening 21 is greater than or equal to 1 mm and is less than half the circumference of the memory ring 2, as shown in Figure 3.

[0032] The memory ring 2 is an open ring structure. When the terminal and the memory ring 2 exceed the transition temperature, the memory ring 2 begins to contract. If the end faces 22 of the memory ring 2 at the opening 21 face each other, and the length of the opening 21 is less than the distance the memory ring 2 contracts, the end faces of the memory ring 2 at the opening 21 will contact each other, preventing further contraction and thus failing to retract the contact spring. This results in insufficient grip between the terminal with the memory ring and the mating terminal, and increases the contact resistance between the terminals, shortening the life of the electrical device and, in severe cases, causing damage such as device burnout. If the length of the opening 21 is greater than half the circumference of the memory ring 2, the memory ring 2 itself cannot form a perfect ring structure and cannot be installed outside the contact segment 13, thus failing to retract the plug cavity.

[0033] In some embodiments, a spiral overlap region exists at the end of the memory ring, and the length of the spiral overlap is less than half the circumference of the memory ring. When the temperature of the memory ring 2 exceeds the transformation temperature, the memory ring 2 contracts. Because the memory ring 2 has an overlap region as shown in Figure 6, the absence of an opening does not affect the tightening of the memory ring 2. If the spiral overlap length is greater than half the circumference of the memory ring, the excess portion will extend outside the mounting ring groove after the memory ring 2 contracts, interfering with the contracted portion of the memory ring 2 body, thereby affecting the contraction of the memory ring 2 within the plug cavity, resulting in insufficient grip between the terminal with the memory ring and the plug terminal, and increased contact resistance between the terminals.

[0034] In some embodiments, the end surface 22 of the memory ring 2 is a flat surface, an inclined surface, an arcuate surface, a spherical surface, or a wavy surface. To prevent the end surface 22 of the memory ring 2 from interfering with the assembly position of the electrical device during terminal assembly, the end surface 22 of the memory ring 2 is configured as a flat surface, an inclined surface, an arcuate surface, a spherical surface, or a wavy surface as needed to meet the requirements of different installation environments.

[0035] In this embodiment, the memory ring 2 can be in direct or intermittent contact with the contact section 13, preferably the memory ring 2 is in direct contact with the contact section 13. The cross section of the memory ring 2 can be circular, elliptical, rectangular, diamond, triangular, polygonal, sector-shaped or trapezoidal.

[0036] The cross-sectional dimensions of the memory ring 2 can be obtained based on needs and a limited number of experiments. Preferably, the cross-sectional dimensions of the memory ring 2 are 0.2-2.1 times the wall thickness of the contact spring 131 .

[0037] The following experiment illustrates the contraction force of the memory ring 2 under different cross-sectional sizes.

[0038] In this experiment, a set of memory rings 2 were constructed with cross-sectional dimensions that were various multiples of the wall thickness of the contact spring 131. The memory rings were constructed from the same nickel-titanium alloy with a transition temperature of 40°C. Thirteen memory rings were used. A precision dynamometer was used to measure the contraction force of the memory rings 2 when the ambient temperature reached 50°C, exceeding the transition temperature. The values ​​were read on the dynamometer. A contraction force greater than 30N was considered ideal.

[0039] Table 1. Contraction force of memory ring 2 at different cross-sectional dimensions

[0040]

[0041] As can be seen from Table 1 above, when the cross-sectional dimensions of the memory ring 2 are 0.2-2.1 times the wall thickness of the contact spring, the measured contraction force meets the ideal value requirement. When the cross-sectional dimensions of the memory ring are less than 0.2 times the wall thickness of the contact spring, the contraction force generated is insufficient to tighten the contact spring 131, causing the mating terminal to fall off. When the cross-sectional dimensions of the memory ring are greater than 2.1 times the wall thickness of the contact spring, the contraction force generated does not increase significantly with the increase in the cross-sectional dimensions of the memory ring, which results in waste of memory alloy material. Therefore, the inventors selected a cross-sectional dimension of the memory ring 2 of 0.2-2.1 times the wall thickness of the contact spring 131 as the preferred solution.

[0042] In this embodiment, the terminal body 1 further comprises a cable connection section 11 and a transition section 12, which are arranged in sequence. The transition section 12 serves as the connecting and transitional area between the cable connection section 11 and the contact section 13, and also serves as the area where the terminal body 1 is assembled and fixed to the electrical device. The cable connection section 11 enables electrical connection to the cable, thereby enabling electrical energy transmission through the mating connection between the terminal body 1 and the mating terminal.

[0043] The cable connecting section 11 has a flat plate structure, a U-shaped structure, a superior arc structure, a cylindrical structure, a cylindrical structure, a bowl-shaped structure, or a polygonal structure. Electrical connection to the cable is typically achieved through crimping or welding. The cable connecting section 11 can be designed in a variety of structures, and different cable connecting section 11 structures can be selected based on the electrical connection requirements and the assembly environment of the electrical device, thereby establishing a stable electrical connection with the cable. Generally, a U-shaped structure, a superior arc structure, a cylindrical structure, or a polygonal structure is suitable for crimping and welding, while a flat plate structure or a bowl-shaped structure is suitable for welding.

[0044] The cable connecting section 11 is connected to the conductor of the cable by one or more of crimping, friction welding, ultrasonic welding, arc welding, laser welding, and resistance welding.

[0045] Crimping uses mechanical deformation to apply pressure, deforming the cable connector 1 and some of the conductors within it. This creates full contact between the conductors and the interior of the cable connector 1 and connects them through friction. Welding methods include ultrasonic welding, resistance welding, arc welding, pressure welding, electromagnetic welding, and laser welding, which weld the cable connector 1 and some of the conductors together to achieve stable electrical and mechanical properties.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] Pressure welding is a method of applying pressure to the weldment to bring the joint surfaces into close contact and produce a certain amount of plastic deformation to complete the welding.

[0050] Electromagnetic welding uses an electromagnetic induction coil to generate a short and very strong current from a pulse generator. The electromagnetic field generated by the induction coil can instantly collide and squeeze the materials to be welded together.

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

[0052] If needed, a sealing ring mounting groove can be provided on the outside of the transition section 12, into which the sealing ring is fitted. The sealing ring is made of rubber, which has a large deformation capacity and waterproof properties. It can be directly compressed outside the transition section 12 and the mating terminal to form a sealed structure, effectively preventing external water from entering the terminal, ensuring the safety of the electrical connection and extending the service life of the terminal.

[0053] The transition section is provided with a sensor mounting hole 122 , in which the temperature sensor is assembled.

[0054] The temperature sensor can be installed at the sensor installation hole 122 at any part of the terminal, and the temperature sensor can be installed in three directions: X, Y, and Z.

[0055] This solution makes the temperature measurement accuracy close to or equal to the theoretical absolute value, and has extremely high detection accuracy and fast output capability.

[0056] The temperature sensor is partially or entirely disposed in the sensor mounting hole 122 .

[0057] The temperature sensor is interference-fitted with the sensor mounting hole 122 .

[0058] The outer wall of the temperature sensor is provided with an external thread, the sensor mounting hole 122 is provided with an internal thread, and the temperature sensor is threadedly connected to the sensor mounting hole 122. The temperature sensor can be installed and then connected to the transmission cable.

[0059] A shielding layer is provided outside the temperature sensor.

[0060] The shielding layer can prevent the temperature sensor data from being interfered with by the outside world, thus ensuring the accuracy of the data.

[0061] 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.

[0062] The sensor mounting hole 122 is provided on the transition section 12 .

[0063] In some embodiments, a temperature acquisition device is provided: an 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 by wire.

[0064] 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.

[0065] In this embodiment, the angle between the insertion direction A of the contact segment 13 and the wiring direction B of the cable connection segment 11 can be greater than 0° and less than or equal to 180°, as shown in Figures 4 and 5. This means that the angle between the contact segment 13 and the cable connection segment 11 can be various to meet the assembly requirements of different scenarios. The angles at which multiple cables access the terminal may vary depending on the actual situation. The inventors have fully considered this and selected a solution greater than 0° and less than or equal to 180° to meet practical needs. This allows designers to select different cable outlet directions based on the actual environment in which the terminal with memory function is to be arranged, thereby reducing the size of the electrical device, optimizing the contact area between the terminal and the wire, and enhancing the electrical performance of the terminal with memory ring.

[0066] Memory ring 2 is made of a memory alloy, a smart metal with memory. Its microstructure has two relatively stable states. At high temperatures, the alloy can be formed into any desired shape. At lower temperatures, the alloy can be stretched, but if it is reheated, it will remember its original shape and return to its original shape. The crystal structure of the memory alloy is different above and below its transformation temperature. However, when the temperature fluctuates above and below the transformation temperature, the memory alloy will contract or expand, causing its shape to change. Taking advantage of this property, the present application selects a memory metal with a transformation temperature of 40°C-70°C to make the memory ring 2, and the memory ring 2 is manufactured to the required size when the temperature is above the transformation temperature.

[0067] In some embodiments, the memory alloy is specifically made of nickel-titanium alloy, a binary alloy composed of nickel and titanium. Due to changes in temperature and mechanical stress, it has two distinct crystal structure phases: austenite and martensite. By using nickel-titanium alloys with different metal contents, a memory ring 2 with a transformation temperature between 40°C and 70°C can be obtained.

[0068] The contact spring 131 has a coating to improve the corrosion resistance of the terminal, improve the electrical conductivity, increase the number of plug-in connections, and better extend the service life of the terminal.

[0069] The coating can be formed by electroplating, chemical plating, magnetron sputtering or vacuum plating.

[0070] Electroplating is the process of plating a thin layer of other metals or alloys on certain metal surfaces using the principle of electrolysis.

[0071] The chemical plating method is a process of depositing metal through a controllable redox reaction under the catalytic action of the metal.

[0072] 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.

[0073] 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.

[0074] 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 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 terminals to obtain better electrical performance and longer service life.

[0075] To demonstrate the impact of different plating materials on the overall performance of 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 2 below.

[0076] The plugging and unplugging times reported in Table 2 below were simulated by fixing the terminals to 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 terminal surface plating. If scratches appeared on the terminal surface plating, 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.

[0077] The corrosion resistance time test in Table 2 below involves placing the terminals in a salt spray test chamber and spraying salt spray at various locations on the terminals. The terminals are then removed, cleaned, and observed for surface corrosion every 20 hours. This constitutes one cycle. Testing is stopped when the surface corrosion area exceeds 10% of the total terminal area. The number of cycles recorded at that time is then recorded. In this example, a cycle count of less than 80 is considered unsatisfactory.

[0078] Table 2: Effects of different plating materials on terminal plug-in and pull-out times and corrosion resistance

[0079]

[0080] As can be seen from Table 2 above, when the coating materials are gold, silver, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver, and silver-gold-zirconium alloy, the experimental results significantly exceed the standard values, and the performance is relatively stable. When the coating materials are nickel, tin, tin-lead alloy, and zinc, the experimental results also meet the requirements. Therefore, the inventors selected the coating materials as 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.

[0081] The plating layer includes a bottom layer and a surface layer.

[0082] In some embodiments, the coating is coated using a multi-layer coating method. After the terminal is processed, there are still many gaps and holes under the microscopic interface of the surface. These gaps and holes are the biggest cause of wear and corrosion of the terminal during use. Therefore, it is necessary to first coat a bottom layer on the surface of the contact section 13 to fill the gaps and holes on the surface, so that the surface of the connecting contact spring 131 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 terminal are better, greatly extending the service life of the terminal.

[0083] 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, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver and silver-gold-zirconium alloy.

[0084] In some embodiments, the thickness of the bottom layer is 0.01 μm-15 μm. The thickness of the bottom layer is 0.1 μm-9 μm.

[0085] In some embodiments, the surface layer has a thickness of 0.5 μm to 55 μm. The surface layer has a thickness of 1 μm to 35 μm.

[0086] To demonstrate the effect of variations in bottom-layer plating thickness on the overall performance of the terminal, the inventors used 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 3 below.

[0087] 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 terminal before power-on 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.

[0088] The corrosion resistance time test in Table 3 below involves placing the terminals in a salt spray test chamber and spraying salt spray at various locations. The terminals are then removed, cleaned, and observed for surface corrosion every 20 hours. This constitutes one cycle. Testing is stopped when the surface corrosion area exceeds 10% of the total terminal area. The cycle count is then recorded. In this example, a cycle count of less than 80 is considered unsatisfactory.

[0089] Table 3: Effects of different base coating thicknesses on terminal temperature rise and corrosion resistance

[0090]

[0091] It can be seen from Table 3 above that when the thickness of the underlying nickel plating layer is less than 0.01 μm, although the temperature rise of the terminal is qualified, the number of corrosion resistance cycles of the terminal is less than 80 due to the thin coating, which does not meet the performance requirements of the terminal. This has a great impact on the overall performance and life of the docking plug-in. 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 thicker underlying coating, the heat generated by the terminal cannot be dissipated, making the temperature rise of the terminal unqualified, and the thicker coating is more likely to fall off from the surface of the terminal, 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 comprehensive effect of the temperature rise and corrosion resistance of the 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.

[0092] Similarly, in order to demonstrate the impact of changes in surface plating thickness on the overall performance of the terminal, the inventors used terminal samples with the same specifications and materials, the same nickel-plated base thickness, and different silver-plated surface thicknesses, and used matching connectors of the same specifications to conduct a series of temperature rise and corrosion resistance time tests. The experimental results are shown in Table 4 below.

[0093] The experimental method is the same as the above experimental method.

[0094] Table 4: Effect of different surface coating thicknesses on temperature rise and corrosion resistance

[0095]

[0096] It can be seen from Table 4 above that when the thickness of the surface silver plating layer is less than 0.5μm, although the temperature rise of the terminal is qualified, the number of corrosion resistance cycles of the terminal is less than 80 because the plating layer is too thin, which does not meet the performance requirements of the terminal. It has a great impact on the overall performance and life of the docking plug-in. 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 55μm, due to the thicker underlying plating layer, the heat generated by the terminal cannot be dissipated, making the temperature rise of the terminal unqualified, and the thicker plating layer is more likely to fall off from the surface of the terminal, 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 0.1μm-55μm. Preferably, the inventors found that when the thickness of the surface coating is 1 μm-35 μm, the comprehensive effect of the temperature rise and corrosion resistance of the 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.

[0097] 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 terminal with a memory ring, in, The terminal with a memory ring comprises a terminal body (1) and a memory ring (2); the terminal body (1) comprises a contact section (13); a plug-in cavity with a variable radial dimension is arranged inside the contact section (13); the memory ring (2) is sleeved outside the contact section (13) and in contact with the contact section (13); and the material of the memory ring (2) is a memory alloy.

2. The terminal with a memory ring according to claim 1, in, The memory ring (2) has a transformation temperature. When the temperature of the terminal with the memory ring is lower than the transformation temperature, the memory ring (2) and the plug-in cavity are both in an expansion state; when the temperature of the terminal with the memory ring is higher than the transformation temperature, the memory ring (2) and the plug-in cavity are both in a contraction state.

3. The terminal with a memory ring according to claim 2, in, The transformation temperature of the memory ring (2) is 40°C-70°C.

4. The terminal with a memory ring according to claim 1, in, The contact segment (13) is provided with at least two slots along the axial direction, and the slots divide the contact segment (13) into at least two contact spring sheets (131).

5. The terminal with a memory ring according to claim 1, in, The inscribed cross-section of the inner surface of the plug-in cavity 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.

6. The terminal with a memory ring according to claim 1, in, The outer surface of the contact section (13) is provided with at least one mounting ring groove (14), and at least one memory ring (2) is respectively sleeved outside each mounting ring groove (14) in a matching manner.

7. The terminal with a memory ring according to claim 1, in, The memory ring (2) is an open ring structure, the length of the opening (21) is greater than or equal to 1 mm, and the length of the opening (21) is less than half of the circumference of the memory ring (2).

8. The terminal with a memory ring according to claim 1, in, There is a spiral overlapping area at the end of the memory ring (2), and the spiral overlapping length is less than half of the circumference of the memory ring (2).

9. The terminal with a memory ring according to claim 1, in, The end surface (22) of the memory ring (2) is a plane, an inclined surface, an arc surface, a spherical surface or a wavy surface.

10. The terminal with a memory ring according to claim 1, in, The shape of the cross section of the body of the memory ring (2) is circular, elliptical, rectangular, rhombus, triangle, polygon, fan-shaped or trapezoidal.

11. The terminal with a memory ring according to claim 10, in, The cross-sectional dimension of the body of the memory ring (2) is 0.2 to 2.1 times the wall thickness of the contact spring piece (131).

12. The terminal with a memory ring according to claim 1, in, The terminal body (1) also comprises a cable connection section (11) and a transition section (12), wherein the cable connection section (11), the transition section (12) and the contact section (13) are arranged in sequence.

13. The terminal with a memory ring according to claim 12, in, The cable connecting section (11) is connected to the conductor of the cable by one or more of crimping, friction welding, ultrasonic welding, arc welding, laser welding and resistance welding.

14. The terminal with a memory ring according to claim 12, in, A sealing ring installation groove is arranged outside the transition section (12), and the sealing ring (121) is sleeved in the sealing ring installation groove.

15. The terminal with a memory ring according to claim 12, in, A sensor mounting hole (122) is provided outside the transition section (12), and the temperature sensor is assembled in the sensor mounting hole (122).

16. The terminal with a memory ring according to claim 15, in, The temperature sensor is interference fit with the sensor mounting hole (122).

17. The terminal with a memory ring according to claim 16, in, The outer wall of the temperature sensor is provided with an external thread, the sensor mounting hole (122) is provided with an internal thread, and the temperature sensor is threadedly connected to the sensor mounting hole (122).

18. The terminal with a memory ring according to claim 15, in, A shielding layer is arranged outside the temperature sensor.

19. The terminal with a memory ring according to claim 15, in, The temperature sensor is an NTC temperature sensor or a PTC temperature sensor.

20. The terminal with a memory ring according to claim 12, in, The angle between the plugging direction of the contact section (13) and the wiring direction of the cable connecting section (11) is greater than 0° and less than or equal to 180°.

21. The terminal with a memory ring according to claim 1, in, The memory alloy is nickel-titanium alloy.

22. The terminal with a memory ring according to any one of claims 1 to 21, in, The contact spring (131) has a coating.

23. The terminal with a memory ring according to claim 22, in, The coating is prepared by electroplating, chemical plating, magnetron sputtering or vacuum plating.

24. The terminal with a memory ring according to claim 22, in, The material of the plating 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.

25. The terminal with a memory ring according to claim 22, in, The plating layer comprises a bottom layer and a surface layer.

26. The terminal with a memory ring according to claim 25, in, 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, silver-antimony alloy, palladium, palladium-nickel alloy, graphite silver, graphene silver and silver-gold-zirconium alloy.

27. The terminal with a memory ring according to claim 25, in, The thickness of the bottom layer is 0.01 μm-15 μm.

28. The terminal with a memory ring according to claim 25, in, The thickness of the bottom layer is 0.1 μm-9 μm.

29. The terminal with a memory ring according to claim 25, in, The thickness of the surface layer is 0.5 μm-55 μm.

30. The terminal with a memory ring according to claim 25, in, The thickness of the surface layer is 1 μm-35 μm.