Connector terminal assembly for large current

Abstract

The connector terminal assembly comprises a male terminal and a female terminal matched with the male terminal, the male terminal comprises a cylindrical conductor, and the connector terminal assembly is characterized in that the female terminal comprises a circular-tube-shaped conductor of which the circumferential tube wall is provided with continuous spiral hollowed-out grooves, the inner diameter of the circular-tube-shaped conductor is smaller than the outer diameter of the cylindrical conductor, and the outer diameter of the circular-tube-shaped conductor is smaller than the outer diameter of the cylindrical conductor. A cutting groove which is communicated with or coincides with the front end of the spiral hollow-out groove is formed in the ring wall of the front end of the circular-tube-shaped conductor; when the cylindrical conductor is inserted into the circular-tube-shaped conductor, the circular-tube-shaped conductor is expanded under the action of the spiral hollow-out groove to wrap the cylindrical conductor, so that the inner circumferential surface of the circular-tube-shaped conductor is tightly attached to the outer circumferential surface of the cylindrical conductor to form surface-to-surface contact. Compared with a line contact type matching structure of a male terminal and a female terminal of a traditional connector terminal assembly, the connector terminal assembly has the advantages that contact resistance can be effectively reduced, and the current-carrying capacity of a connector is improved on the premise that materials are not changed and the material consumption is not increased.

Description

Technical Field

[0001] The invention relates to the technical field of structural manufacturing of connector terminals, and in particular to a connector terminal assembly for large currents. Background Art

[0002] At present, terminal connector assemblies are widely used in power supply line connection devices of network energy equipment, base stations, industrial power distribution equipment and new energy vehicles. Taking the connector terminal assembly of the charging and plugging device of new energy vehicles as an example, its structure usually includes male terminals and female terminals. The male terminal is usually a cylindrical conductor, which is generally installed and fixed on the charging socket, while the female terminal adopts an elastic contact conductor with a socket, which is mainly arranged on the gun head of the charging gun and is wrapped and protected by a tubular insulating shell on the outside.

[0003] The connector terminal assembly of the traditional new energy charging plug-in device usually has one or two raised springs inside its main body to contact the male terminal. However, due to point contact, the contact resistance is large. As the charging power continues to increase, the temperature rise is significant, resulting in poor contact conductivity and weak current carrying capacity, which cannot meet the requirements of high-current charging. For this reason, the female terminals in the industry currently generally adopt a split-groove structure, such as the publication numbers CN221632874U, CN 211017481U, and CN217768849U, which all disclose this split-groove terminal structure. Its characteristic is that multiple springs arranged in a circle and enclosed in a cylindrical shape are used to achieve elastic contact with the male terminal, changing point contact to line contact, thereby further reducing contact resistance and enhancing the current carrying capacity of the terminal, so as to further meet the requirements of high-current charging.

[0004] However, in practice, as the charging power of new energy vehicles continues to increase, the above-mentioned slot-type terminal structure still exposes the shortcomings of large contact resistance and weak current carrying capacity, which cannot meet the requirements of high current charging and has the problem of low charging efficiency, which urgently needs to be improved.

[0005] At present, the current carrying capacity of connector terminal components for high current is mainly improved in the industry through the following two methods: 1. Replace materials with higher conductivity.

[0006] However, if the structure remains unchanged, replacing materials can indeed have an immediate effect, but it will also increase the cost of the product.

[0007] , reduce impedance by increasing the conductor cross-section of the terminal.

[0008] Increasing the cross-sectional size of the conductor and increasing the number of contact pairs can reduce the impedance of the contact part of the terminal assembly to a certain extent, and indirectly improve the current carrying capacity of the terminal. However, this method will also limit the design of other components of the charging plug device due to the increase in the overall size, resulting in the entire appearance of the product also needing to be adjusted synchronously, which increases the overall cost of the charging plug device and greatly reduces the aesthetics of the product.

[0009] In summary, there is currently no practical connector terminal assembly structural solution in the industry that can achieve the purpose of improving current carrying capacity without changing the material or increasing the material usage. Summary of the invention

[0010] The object of the present invention is to provide a connector terminal assembly for large currents, which can improve the current carrying capacity of the connector without changing the material or increasing the material usage.

[0011] The technical solution of the present invention is: a connector terminal assembly for large current, including a male terminal and a female terminal matching therewith, the male terminal including a cylindrical conductor, characterized in that the female terminal includes a tubular conductor with a continuous spiral hollow groove on the circumferential tube wall, the inner diameter of the tubular conductor is smaller than the outer diameter of the cylindrical conductor, and a groove connected to or overlapping with the front end of the spiral hollow groove is opened on the front end ring wall of the tubular conductor; when the cylindrical conductor is inserted into the tubular conductor, the tubular conductor is expanded under the action of the spiral hollow groove to wrap the cylindrical conductor, so that the inner circumferential surface of the tubular conductor is tightly attached to the outer circumferential surface of the cylindrical conductor to form surface-to-surface contact.

[0012] Furthermore, the female terminal in the present invention also includes a wiring head fixedly connected to the end of the cylindrical conductor.

[0013] Furthermore, the wall surface of the front end ring wall of the circular tubular conductor in the present invention is a straight surface perpendicular to its axis, and the groove is a straight groove parallel to the axis of the circular tubular conductor, which is connected to the front end of the spiral hollow groove.

[0014] Furthermore, the circular tubular conductor in the present invention is made by drilling a hole in a cylindrical conductor along the axis and then milling the spiral hollow groove on the outer periphery, and the diameter of the drilled hole is the inner diameter of the circular tubular conductor; or the circular tubular conductor is made by spirally winding a metal spring sheet along the axial direction of a core rod with equally spaced thread pitches, and the outer diameter of the core rod is the inner diameter of the circular tubular conductor.

[0015] Furthermore, the circular tubular conductor in the present invention has a closed end, which can be closed by integral molding or by welding a sealing plate or a sealing block.

[0016] Furthermore, the terminal block in the present invention is a columnar component, a tubular component, or a flat component, and the terminal block is fixedly connected to the end of the circular tubular conductor by riveting, electric welding, or ultrasonic welding.

[0017] The working principle of the present invention is as follows: Before the male terminal and the female terminal are mated and plugged, the inner diameter of the circular tubular conductor of the female terminal is smaller than the outer diameter of the cylindrical conductor of the male terminal. As the cylindrical conductor of the male terminal is inserted, the section of the circular tubular conductor that first contacts the cylindrical conductor will expand under the action of the spiral hollow groove preset on the circular tubular conductor. The expanded inner diameter is equal to the outer diameter of the cylindrical conductor, forming an effect of wrapping the cylindrical conductor. As the cylindrical conductor is inserted into place, the entire circular tubular conductor is expanded, and its inner circumference is tightly attached to the outer circumference of the cylindrical conductor to form a surface-to-surface contact. After the cylindrical conductor is pulled out, the inner circumference of the circular tubular conductor is restored due to the absence of external force.

[0018] Regarding the calculation of contact resistance of male and female terminals, Holm gave the following reference formula: ,(μΩ); In the formula, K is the material coefficient, F is the contact pressure, and m is the contact form coefficient; For point contact, m = 0.5; For line contact, m = 0.6-0.7; For surface contact, m=1.

[0019] The male and female terminal contact pairs of existing connector terminal assemblies are designed to be line contact, while the present invention adopts surface contact. Under the condition that the material and pressure remain unchanged, taking the common lateral pressure F=100N as an example, according to the above formula, it can be known that the final contact resistance obtained by this scheme can be reduced by half. Further, from the contact position heat generation power P=I2R, it can be known that the contact position heat generation power of the connector terminal assembly of this scheme is 1 / 2 of the conventional design when in use, that is, the current carrying capacity can be increased by 41%.

[0020] Compared with the prior art, the present invention provides a connector terminal assembly for large currents, which has the following beneficial effects: 1. The present invention maximizes the conductive properties of the material. It improves the structure of the female terminal, changes the contact form of the male and female terminals, changes the line contact to the surface contact, effectively reduces the contact resistance, and thus ensures that the current carrying capacity of the connector is improved without changing the material and increasing the material consumption.

[0021] The annular force between the inner circumference of the female terminal and the outer circumference of the male terminal of the present invention is uniform, the yield strength is low, and the service life is longer: the surface contact deformation is small, the material is in the elastic deformation range, and the service life is increased to more than 15,000 plug-in and pull-out times. The existing reed-type plug-in terminal assembly can only meet less than 10,000 times.

[0022] , the contact part of the female terminal (and the male terminal) in the present invention is dimensionally stable, and the processing is easier to control. In conventional terminal assemblies, the contact part of the female terminal is formed by bending or mechanical extrusion. After the external force of the male terminal is removed, the contact part will rebound, and the final shape will deviate from the design value to a certain extent. This range is related to the material batch, the time the external force is maintained, and the degree of wear of the tooling that applies the force. In the present invention, the contact part of the female terminal adopts the inner circumferential surface of the circular tubular conductor for overall contact. The shape changes little after the male terminal is expanded and removed and contracted. The inner circumferential surface can be processed by mechanical drilling or spring winding, and the processing accuracy and stability of the inner diameter are higher.

[0023] , the material used in the present invention is more economical, and the production cost can be saved.

[0024] At present, the inner circumference of the conventional split-slot structure female terminal needs to be bent or extruded to form an inner convex structure as the contact part with the male terminal. The radial height of the inner convex structure is the so-called bottom hole gap B. Therefore, the outer diameter D of the conventional split-slot structure female terminal is D = A + 2B + 2C, where A is the outer diameter of the matching male terminal, C is the wall thickness of the female terminal, and 2B is usually 0.2-1mm. In the female terminal structure of the present invention, since the inner circumference arc surface is used for overall contact and there is no bottom hole gap design, the outer diameter of the female terminal is d = a-2b + 2c, where a is the outer diameter of the matching male terminal, c is the wall thickness, and 2b is the difference between the inner diameter of the cylindrical conductor after the inner circumference is expanded and the inner diameter of the bottom hole, which is usually 0.2-0.5mm.

[0025] By comparison, under the premise that the outer diameters of the male terminals in the terminal assemblies of this case and conventional technology are the same (i.e. A=a) and the wall thicknesses of the female terminals are the same (i.e. C=c), it can be obtained that D>d, that is, the outer diameter of the female terminal in this case will be smaller than that of the conventional design, thereby achieving material savings.

[0026] The terminal assembly of the present invention has a smaller installation space requirement as a whole and can be more flexibly applied in narrow scenes: the processed external dimensions are small, and when applied to charging equipment products, more room can be provided for other components to play.

[0027] The female terminal in the terminal assembly of the present invention has a simple structure and is easy to process. Compared with the current assembled terminal assembly, it is a single part and can meet higher current carrying requirements without assembly.

[0028] The objects, advantages and features of the present invention will be illustrated and explained by the following non-limiting description of preferred embodiments thereof, which are given by way of example only with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall three-dimensional structure of a specific embodiment of the present invention (male and female terminals are not plugged in); Figure 2 for Figure 1 A side view of the state change of the male and female terminals during the plugging process in the embodiment; Figure 3 A side view of male and female terminals in an existing connector terminal assembly when plugged and matched; Figure 4 for Figure 1 A side view of the male and female terminals of the embodiment when they are plugged in and matched; Figure 5 It is a schematic diagram of the overall three-dimensional structure of the second embodiment of the present invention; Figure 6 It is a schematic diagram of the overall three-dimensional structure of the third embodiment of the present invention.

[0030] In the figure: 1, male terminal; 101, cylindrical conductor; 2, female terminal; 201, tubular conductor; 201a, spiral hollow groove; 201b, front end ring wall; 201c, cut groove; 202, terminal head. DETAILED DESCRIPTION

[0031] The following will be combined Figure 1-Figure 6 As shown, the specific implementation of the connector terminal assembly for large current provided by the present invention is clearly and completely described. Obviously, the embodiments described below are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] Embodiment 1: First combine Figure 1 As shown, the connector terminal assembly for high current provided in this embodiment has a male terminal 1 and a female terminal 2 matched therewith as in conventional technology. The male terminal 1 includes a cylindrical conductor 101. The core improvement of the present invention is that the female terminal 2 is composed of a circular tubular conductor 201 and a terminal head 202 fixedly connected to the end thereof. A continuous spiral hollow groove 201a is provided on the circumferential tube wall of the circular tubular conductor 201, and the inner diameter of the circular tubular conductor 201 is smaller than the outer diameter of the cylindrical conductor 101. A groove 201c communicating with the front end of the spiral hollow groove 201a is provided on the front end ring wall 201b of the circular tubular conductor 201.

[0033] Specific as Figure 1As shown, in this embodiment, the wall surface of the front end ring wall 201b of the circular tubular conductor 201 is a straight surface perpendicular to its axis, and the groove 201c is a straight groove parallel to the axis of the circular tubular conductor 201, which is connected to the front end of the spiral hollow groove 201a.

[0034] In this embodiment, the circular tubular conductor 201 has a closed end.

[0035] In this embodiment, the circular tubular conductor 201 is made by drilling a hole (blind hole) along the axis of a columnar conductor and then milling out the spiral hollow groove 201 a on the periphery. The diameter of the drilled hole (blind hole) is the inner diameter of the circular tubular conductor 201 .

[0036] Still combined Figure 1 As shown, the terminal head 202 in this embodiment is a tubular component, which is fixed to the closed end of the round tubular conductor 201 by electric welding.

[0037] Combination Figure 2 As shown, after the cylindrical conductor 101 is inserted into the tubular conductor 201, the tubular conductor 201 is expanded by the spiral hollow groove 201a to wrap the cylindrical conductor 101, so that the inner circumference of the tubular conductor 201 is in close contact with the outer circumference of the cylindrical conductor 101 to form a surface-to-surface contact.

[0038] Regarding the calculation of the contact resistance of the male terminal 1 and the female terminal 2, Holm gave the following reference formula: ,(μΩ); In the formula, K is the material coefficient, F is the contact pressure, and m is the contact form coefficient; For point contact, m = 0.5; For line contact, m = 0.6-0.7; For surface contact, m=1.

[0039] The male and female terminal contact pairs of existing connector terminal assemblies are designed to be line contact, while the present invention adopts surface contact. Under the condition that the material and pressure remain unchanged, taking the common lateral pressure F=100N as an example, according to the above formula, it can be known that the final contact resistance obtained by this scheme can be reduced by half. Further, from the contact position heat generation power P=I2R, it can be known that the contact position heat generation power of the connector terminal assembly of this scheme is 1 / 2 of the conventional design when in use, that is, the current carrying capacity can be increased by 41%.

[0040] Therefore, it can be said that the connector terminal assembly of the present invention maximizes the conductive properties of the material. It improves the structure of the female terminal 2, changes the contact form between the male terminal 1 and the female terminal 2, and changes the line contact to the surface contact, thereby effectively reducing the contact resistance, thereby ensuring that the current carrying capacity of the connector is improved without changing the material and increasing the material consumption.

[0041] In addition, in the present invention, the inner circumference of the female terminal 2 and the outer circumference of the male terminal 1 are subjected to uniform annular force and have low yield, so the service life is also longer: the surface contact deformation is small, the material is in the elastic deformation range, and the service life is increased to more than 15,000 plug-in and pull-out times, while the existing reed-type terminal assembly can only meet less than 10,000 times.

[0042] In addition, the connector terminal assembly of the present invention also uses less material, which is mainly reflected in the female terminal 2. Figure 3 and Figure 4 The figure is used to compare and illustrate the difference in structural dimensions between the present invention and conventional technology, and further explain the difference in material usage.

[0043] like Figure 3 As shown, for the convenience of explanation, we give the same markings to the male and female terminals as in this case (i.e., the male terminal is 1 and the female terminal is 2). The inner circumference of the conventional split-slot structure female terminal 2 needs to be bent or extruded to form an inner convex structure as the contact part with the male terminal 1. The radial height of the inner convex structure is the so-called bottom hole gap B. Therefore, the outer diameter D of the conventional split-slot structure female terminal 2 is D=A+2B+2C, where A is the outer diameter of the paired male terminal 1, C is the wall thickness of the female terminal 2, and 2B is usually 0.2-1mm.

[0044] Combined with Figure 4 As shown, in the structure of the female terminal 2 of the present invention, since the inner circumferential arc surface is in overall contact and there is no bottom hole gap design, the outer diameter d of the female terminal 2 is = a-2b+2c, wherein a is the outer diameter of the paired male terminal 1, c is the wall thickness, and 2b is the difference between the inner diameter of the circular tubular conductor 201 after the inner circumference is expanded and the inner diameter of the bottom hole (i.e., the tube hole when the circular tubular conductor 201 is not expanded), which is usually 0.2-0.5mm.

[0045] By comparison, under the premise that the outer diameter of the male terminal 1 matched with that of the terminal assembly in the present case and the conventional technology is the same (i.e. A=a) and the wall thickness of the female terminal 2 is equal (i.e. C=c), it can be obtained that D>d, that is, the outer diameter of the female terminal 2 in the present case will be smaller than that of the conventional design as a whole, thereby achieving material savings.

[0046] Example 2: Figure 5As shown, another embodiment of a connector terminal assembly for high current of the present invention is provided. It has a male terminal 1 and a female terminal 2 matched therewith as in the first embodiment. The male terminal 1 includes a cylindrical conductor 101, and the female terminal 2 is composed of a tubular conductor 201 and a terminal head 202 fixedly connected to the end thereof. The structure of the tubular conductor 201 is exactly the same as that of the first embodiment, and the details can be referred to the description of the first embodiment. However, the difference from the first embodiment is that the terminal head 202 in the present embodiment is a flat component and is fixedly connected to the end of the tubular conductor 201 by ultrasonic welding. Of course, the working principle and implementation effect of the present embodiment can be referred to the description of the first embodiment.

[0047] Example 3: Figure 6 As shown, another embodiment of a connector terminal assembly for large current of the present invention has a male terminal 1 and a female terminal 2 matching therewith, the male terminal 1 includes a cylindrical conductor 101, and the female terminal 2 is composed of a tubular conductor 201 and a terminal head 202 fixedly connected to its end.

[0048] In this embodiment, the female terminal 2 is composed of a circular tubular conductor 201 and a terminal head 202 fixedly connected to the end thereof. A continuous spiral hollow groove 201a is provided on the circumferential wall of the circular tubular conductor 201, and the inner diameter of the circular tubular conductor 201 is smaller than the outer diameter of the cylindrical conductor 101. In this embodiment, a groove 201c is provided on the front ring wall 201b of the circular tubular conductor 201, and the groove 201c completely overlaps with the front end of the spiral hollow groove 201a, that is, the starting point of the front end of the spiral hollow groove 201a is provided on the front ring wall 201b of the circular tubular conductor 201, so it does not have a straight groove as in the first embodiment.

[0049] In actual implementation, the circular tubular conductor 201 in this embodiment is formed by spirally winding a metal spring sheet along the axial direction of a core rod at an evenly spaced thread pitch, and the outer diameter of the core rod is the inner diameter of the circular tubular conductor 201. Therefore, compared with Embodiment 1, the wall surface of the front end ring wall 201b of the circular tubular conductor 201 in this embodiment is not a straight surface.

[0050] Still combined Figure 6 As shown, the circular tubular conductor 201 in this embodiment also has a closed end, and the terminal head 202 is a tubular component, which is riveted to the closed end of the circular tubular conductor 201.

[0051] The working principle and implementation effect of this embodiment can also refer to the description of embodiment 1.

[0052] Of course, the above are only specific application examples of the present invention and do not constitute any limitation on the protection scope of the present invention. In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection claimed by the present invention.

Claims

1. A connector terminal assembly for high current, comprising a male terminal (1) and a female terminal (2) mating therewith, wherein the male terminal (1) comprises a cylindrical conductor (101), characterized in that The female terminal (2) comprises a tubular conductor (201) having a continuous spiral hollow groove (201a) on a circumferential tube wall, the inner diameter of the tubular conductor (201) being smaller than the outer diameter of the cylindrical conductor (101), and a groove (201c) communicating with or overlapping the front end of the spiral hollow groove (201a) is formed on the front end ring wall (201b) of the tubular conductor (201); when the cylindrical conductor (101) is inserted into the tubular conductor (201), the tubular conductor (201) is stretched open by the spiral hollow groove (201a) to wrap around the cylindrical conductor (101), so that the inner circumferential surface of the tubular conductor (201) and the outer circumferential surface of the cylindrical conductor (101) are in close contact with each other to form a surface-to-surface contact.

2. A connector terminal assembly for high current according to claim 1, characterized in that The female terminal (2) further comprises a connection head (202) fixedly connected to the end of the circular tubular conductor (201).

3. A connector terminal assembly for high current according to claim 1, characterized in that The wall surface of the front end ring wall (201b) of the circular tubular conductor (201) is a straight surface perpendicular to its axis, and the groove (201c) is a straight groove parallel to the axis of the circular tubular conductor (201), which is connected to the front end of the spiral hollow groove (201a).

4. A connector terminal assembly for high current according to claim 1, characterized in that The circular tubular conductor (201) is made by drilling a hole through the axis of a columnar conductor and then milling the spiral hollow groove (201a) on the outer circumference, and the diameter of the drilled hole is the inner diameter of the circular tubular conductor (201); or the circular tubular conductor (201) is made by spirally winding a metal spring sheet along the axial direction of a core rod at an evenly spaced thread pitch, and the outer diameter of the core rod is the inner diameter of the circular tubular conductor (201).

5. A connector terminal assembly for high current according to claim 1 or 2, characterized in that The cylindrical conductor (201) has a closed end.

6. A connector terminal assembly for high current according to claim 2, characterized in that The connection head (202) is a columnar component, a tubular component, or a flat component, and the connection head (202) is fixedly connected to the end of the circular tubular conductor (201) by riveting, electric welding, or ultrasonic welding.

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