A fastener for electric busbar connection and electric busbar connection system

Abstract

The application provides a fastener for electric busbar connection and an electric busbar connection system. The fastener for electric busbar connection comprises a flange part, a rod body connected to one end of the flange part in the axial direction, a first interference fitting part, a second interference fitting part and a guide part arranged in sequence from the end connected to the flange part, the outer diameters of the guide part, the second interference fitting part, the first interference fitting part and the flange part increase in sequence, the difference between the outer diameter of the first interference fitting part and the outer diameter of the second interference fitting part is 0.5mm-1.0mm, and an inner hole extends axially inward from the end of the rod body away from the flange part, and a thread is formed on the inner wall of the inner hole. The fastener for electric busbar connection is simple to process, can be connected to the electric busbar through fast rivet connection with low pressing force, has reliable connection strength and is not prone to loosening during long-term use.

Description

Technical Field

[0001] This invention belongs to the field of conductive connection technology for new energy vehicles, and particularly relates to a fastener and conductive busbar connection system for connecting conductive busbars. Background Technology

[0002] With the rapid development of new energy vehicle technology, high-voltage electrical systems such as batteries and electric drives are using a large number of conductive busbars (copper busbars and aluminum busbars) to achieve high current transmission. The reliability of the connection between conductive busbars, the assembly efficiency, and the manufacturing cost directly affect the overall performance of the high-voltage electrical system.

[0003] In existing technologies, for conductive busbar connections requiring long conductive bushings, welding is commonly used to connect the conductive busbar and the conductive bushing as a single unit. However, welding has several practical drawbacks: firstly, the welding process is time-consuming and costly, requiring strict control of welding heat, making process management difficult; secondly, welding inevitably carries the risk of incomplete welds, which increase contact resistance and can easily lead to localized overheating under high current operation, posing safety hazards. Furthermore, the high temperatures generated during welding alter the metallographic structure of the conductive busbar and conductive bushing, causing a decline in their mechanical properties. Under the vibration and alternating thermal cycling conditions of vehicle operation, material creep is prone to occur at the weld joint, leading to torque attenuation, loosening of the conductive connection interface, and continuous deterioration of contact resistance, ultimately reducing the reliability of the high-voltage circuit connection.

[0004] Aside from welding, conventional press-fit fastener connection schemes mainly rely on the press-fit deformation of the flange to achieve torsional and thrust resistance, requiring a large amount of interference to meet the connection strength requirements. When assembly requires the use of low-rigidity copper or aluminum conductive bushings to transmit press-fit force, a large amount of interference will result in excessive press-fit force, which can easily cause the conductive bushing to deform or crush under pressure, making it unsuitable for busbar assembly scenarios with long conductive bushings. Summary of the Invention

[0005] In view of the problems existing in the prior art, the main objective of the present invention is to provide a fastener and a conductive busbar connection system for connecting conductive busbars. The fastener provided for connecting conductive busbars is simple to process, can use a low pressing force to achieve a quick crimp connection with the conductive busbar, and has reliable connection strength and is not easy to loosen after long-term use.

[0006] The objective of this invention is achieved through the following technical solution: This invention provides a fastener for connecting conductive busbars, comprising: Flange section; The rod body is axially connected to one end of the flange portion. From the end connected to the flange portion, it is provided with a first interference fit portion, a second interference fit portion, and a guide portion in sequence. The outer diameters of the guide portion, the second interference fit portion, the first interference fit portion, and the flange portion increase in sequence, and the difference between the outer diameter of the first interference fit portion and the outer diameter of the second interference fit portion is 0.5mm-1.0mm. An inner hole extends axially inward from one end of the rod body away from the flange, and a thread is formed on the inner wall of the inner hole.

[0007] As a further description of the above technical solution, the first interference fit part and the second interference fit part are respectively one of the straight knurled structure, the oblique knurled structure or the polygonal protrusion structure.

[0008] As a further description of the above technical solution, it also includes a groove, which is located axially between the flange and the rod, and the groove surrounds the outer periphery of the rod.

[0009] As a further description of the above technical solution, it also includes a material discharge section, which is disposed between the flange section and the groove section, so as to drive the material of the connected parts into the groove section during riveting. The outer diameter of the discharge section is smaller than the outer diameter of the flange section but larger than the outer diameter of the first interference fit section.

[0010] As a further description of the above technical solution, the fastener is an integrally molded part.

[0011] The present invention also provides a conductive busbar connection system, comprising: A first conductive busbar, wherein the first conductive busbar is provided with a first mounting hole; A conductive bushing, wherein the conductive bushing is provided with a mating hole; A second conductive busbar, the second conductive busbar being provided with a second mounting hole; and Fasteners for conductive busbar connections as described above; wherein, The fastener's rod passes through the first mounting hole and the mating hole. The first mounting hole is press-fitted with the first interference fit part. The mating hole is press-fitted with the second interference fit part and clearance-fitted with the guide part. In the axial direction, the end face of the flange part facing the rod part abuts against the end face of the first conductive busbar away from the conductive bushing. A fastening screw, comprising a main body and a head connected to one axial end of the main body, wherein the outer diameter of the head is larger than the outer diameter of the main body, wherein the main body passes through the second mounting hole and is screwed into the inner hole, so that the head presses the second conductive busbar against the conductive bushing on the side away from the first conductive busbar, thereby causing the conductive bushing to abut against the first conductive busbar and the second conductive busbar respectively, so as to electrically connect the first conductive busbar and the second conductive busbar.

[0012] As a further description of the above technical solution, the outer diameter of the guide portion is smaller than the inner diameter of the mating hole; The outer diameter of the first interference fit is larger than the inner diameter of the first mounting hole; The outer diameter of the second interference fit part is larger than the inner diameter of the fit hole and smaller than the inner diameter of the first mounting hole.

[0013] As a further description of the above technical solution, the mating hole of the conductive bushing is a straight hole; or, The wall surface for forming the mating hole includes a first inner peripheral wall and a second inner peripheral wall, wherein the inner diameter of the first inner peripheral wall is larger than the inner diameter of the second inner peripheral wall; and the inner diameter of the second inner peripheral wall is larger than the outer diameter of the body portion of the fastening screw; wherein... The first inner peripheral wall forms the end of the mating hole away from the second conductive busbar to have an interference fit with the second interference fit portion and a clearance fit with the guide portion; The second inner peripheral wall forms the mating hole near the end of the second conductive busbar, and is located axially between the end of the rod body away from the flange and the end face of the second conductive busbar facing the first conductive busbar, so that the main body of the fastening screw can pass through.

[0014] As a further description of the above technical solution, the first conductive busbar, the second conductive busbar, and the conductive bushing are made of copper or aluminum, respectively.

[0015] As a further description of the above technical solution, the fastener is riveted to the first conductive busbar.

[0016] By employing the above technical solutions, the outstanding effects of this invention are as follows: 1. The anti-push function of the fastener for connecting conductive busbars provided by the present invention is mainly achieved by the first interference fit part and the second interference fit part (knurled structure). The knurled structure can be directly formed by cold forming process. Except for the internal thread, no secondary processing is required, which simplifies the manufacturing process and reduces the manufacturing cost. 2. The anti-torsion and anti-push function of the fastener for connecting conductive busbars provided by the present invention is mainly undertaken by the first interference fit part and the second interference fit part. The two interference fit parts are set as knurled structures, with small interference amount and low installation force required. This can effectively avoid the situation where the conductive bushings of materials with low stiffness such as copper and aluminum are easily deformed or crushed when transmitting installation force due to the traditional large interference amount riveting structure. 3. The conductive busbar connection system of the present invention uses mechanical riveting instead of welding, which eliminates welding process time, welding heat control and poor weld detection, etc., resulting in higher assembly efficiency. The conductive bushings abut against the first conductive busbar and the second conductive busbar respectively to form conductive contact surfaces, forming a long-term reliable current path. Through the double interference fit of the first interference fit and the second interference fit, the connection strength is reliable and it is not easy to loosen after long-term use. Attached Figure Description

[0017] Figure 1 This is an axial view of the fasteners used for connecting conductive busbars in an embodiment of the present invention; Figure 2 This is a half-sectional schematic diagram of the fastener used for connecting the conductive busbar in an embodiment of the present invention; Figure 3 This is a half-section exploded isometric view of the conductive busbar connection system in the first embodiment of the present invention; Figure 4 This is a half-section axial view of the conductive busbar connection system in the first embodiment of the present invention; Figure 5 This is a schematic diagram of the structure after the fastener is connected to the first conductive busbar and the conductive bushing in the first embodiment of the present invention; Figure 6 This is a half-sectional view of the conductive busbar connection system in the first embodiment of the present invention; Figures 7 to 10 This is a schematic diagram showing the state in which the first conductive busbar and the conductive bushing are installed on the fastener in two steps in the first embodiment of the present invention. Figure 11 This is a schematic diagram of a state in which the first conductive busbar and the conductive bushing are simultaneously installed on the fastener in the second embodiment of the present invention. Figure 12 This is a full cross-sectional schematic diagram of the conductive bushing in the third embodiment of the present invention; Figure 13 This is a half-section axial view of the conductive bushing in the third embodiment of the present invention; Figure 14 This is a full sectional schematic diagram of the conductive busbar connection system in the third embodiment of the present invention; Figure 15 This is a half-section axial side view of the conductive busbar connection system in the third embodiment of the present invention.

[0018] Explanation of icon numbers: 1. Fastener; 11. Flange; 12. First interference fit; 13. Second interference fit; 14. Guide; 15. Inner hole; 16. Groove; 17. Discharge section; 2. First conductive busbar; 21. First mounting hole; 3. Conductive bushing; 31. Mating hole; 311. First inner peripheral wall; 312. Second inner peripheral wall; 4. Second conductive busbar; 41. Second mounting hole; 5. Fastening screws; 51. Main body; 52. Head. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be noted that the terms "upper," "middle," "lower," "inner," "outer," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or mechanism referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0021] Please see Figures 1 to 15 This invention discloses a fastener 1 for connecting conductive busbars and a conductive busbar connection system. The disclosed fastener 1 for connecting conductive busbars includes: Flange 11; The rod body is axially connected to one end of the flange portion 11. From the end connected to the flange portion 11, it is sequentially provided with a first interference fit portion 12, a second interference fit portion 13, and a guide portion 14. The outer diameters of the guide portion 14, the second interference fit portion 13, the first interference fit portion 12, and the flange portion 11 increase sequentially, and the difference between the outer diameter of the first interference fit portion 12 and the outer diameter of the second interference fit portion 12 is 0.5mm-1.0mm. The inner hole 15 extends axially inward from one end of the rod body away from the flange portion 11, and the inner wall of the inner hole 15 is threaded.

[0022] In the above configuration, the flange 11 serves as the axial positioning and pull-out resistance structure for the fastener 1. It has the largest outer diameter and abuts against the surface of the external connector (such as the first conductive busbar 2) after the fastener 1 is pressed in, preventing the fastener 1 from coming out. The rod body serves as the main structure of the fastener 1, extending axially from one end of the flange 11. It sequentially forms three functional sections from the end connected to the flange 11: a first interference fit section 12, a second interference fit section 13, and a guide section 14. The guide section 14 has the smallest outer diameter and is used to first enter the mating hole 31 of the external mating component (such as the conductive bushing 3) during installation, serving as a guide and positioning element. The second interference fit section 13 has a larger outer diameter than the guide section 14 and forms an interference fit with the mating hole 31 of the external mating component, providing anti-torsion and anti-push capabilities. The first interference fit section 12 has a larger outer diameter than the second interference fit section 13 and forms an interference fit with the mounting hole of the external connector (such as the first conductive busbar 2), further providing anti-torsion and anti-push capabilities. The difference between the outer diameter of the first interference fit part 12 and the outer diameter of the second interference fit part 13 is generally 0.5mm-1.0mm. This size difference ensures that there is sufficient and reliable interference between the first interference fit part 12 and the mounting hole of the first conductive busbar 2. The second interference fit part 13, with its relatively small outer diameter, ensures an effective interference fit with the mating hole 31 of the conductive bushing 3 while avoiding excessive compression or damage to the conductive bushing 3, which has lower rigidity. This allows the interference of the two interference fit parts to match the material and rigidity of their respective mating objects. Thus, the design of the outer diameters of the guide part 14, the second interference fit part 13, the first interference fit part 12, and the flange part 11 increasing sequentially allows each section to gradually enter the corresponding assembly hole during the press-fitting process, dispersing the resistance step by step, thereby effectively reducing the overall press-fitting force. The inner hole 15 extends axially inward from the end of the rod body away from the flange part 11, and the thread on its inner wall is used to mate with the external thread of the external fastener 1 (such as the fastening screw 5). The external fastener 1 passes through another external connector (such as the second conductive busbar 4) and is screwed into the inner hole 15, thereby pressing the external connector onto the external mating part. Thus, by using only a single fastener 1 structure, multiple functions such as guiding and positioning, multi-stage interference fit anti-torsion and anti-pull, anti-pull, and threaded connection can be achieved simultaneously, completely replacing the welding connection method between the two external connectors and the external mating part, and significantly improving the connection reliability and assembly efficiency of the two external connectors and the external mating part.

[0023] Please see Figures 1 to 15Specifically, in the first to third embodiments, the first interference fit portion 12 and the second interference fit portion 13 are respectively straight-knurled structures. More specifically, the straight-knurled structure refers to a knurled structure where the knurling pattern is parallel to the axis of the rod body, that is, a series of straight teeth extending axially are formed on the outer peripheral wall of the rod body. When the rod body is press-fitted into the mating mounting hole or mating hole 31, these straight teeth will form an interference fit with the inner wall of the hole, thereby providing anti-torsion and anti-push capabilities. At the same time, since the outer diameters of the guide portion 14, the second interference fit portion 13, the first interference fit portion 12, and the flange portion 11 increase sequentially, the two interference fit portions of the straight-knurled structure at the cold-forging point can be directly passed through, making the overall processing of the fastener 1 more convenient. Of course, in other embodiments, the first interference fit portion 12 and the second interference fit portion 13 may also be other protruding structures, such as a knurled structure (a knurled structure in which the knurling pattern forms a certain angle with the axis of the rod), a protrusion with a hexagonal or quadrilateral cross section, etc., to form an interference fit with the inner wall of the mating mounting hole or mating hole 31 to provide anti-torsion and anti-push capabilities.

[0024] Specifically, in the first to third embodiments, the fastener 1 further includes a groove 16, which is located axially between the flange 11 and the rod, and surrounds the outer periphery of the rod. In other words, the groove 16 is an annular groove located between the end face of the flange 11 facing the rod and the root of the rod. Its function is to provide a space for the material flow of the external connector when the fastener 1 is press-fitted and fixed to the external connector. That is, under the action of the press-fitting force, part of the material of the external connector is squeezed and undergoes plastic flow, embedding itself into the groove 16 to form an axial locking structure. The groove 16 is located axially between the flange 11 and the rod, ensuring that the groove 16 is close to the flange 11. This allows the material of the external connector embedded in the groove 16 to work together with the flange 11 to provide bidirectional axial restraint for the fastener 1. Specifically, the flange 11 abuts against the surface of the external connector from the outside, resisting the force that pulls the fastener 1 outward, while the material embedded in the groove 16 forms an axial barrier from the inside, resisting the force that pushes the fastener 1 inward. Both provide axial restraint in two opposite directions, jointly enhancing the axial holding force of the fastener 1.

[0025] Specifically, in the first to third embodiments, the fastener 1 further includes a discharge section 17, which is disposed between the flange portion 11 and the groove portion 16 to drive the material of the connected parts into the groove portion 16 during riveting. The outer diameter of the discharge section 17 is smaller than the outer diameter of the flange portion 11 and larger than the outer diameter of the first interference fit portion 12. More specifically, the discharge section 17 is an annular protrusion structure between the flange portion 11 and the groove portion 16, with its outer diameter between the flange portion 11 and the first interference fit portion 12, forming a stepped profile in the axial direction. The function of the discharge section 17 is equivalent to an annular punch: during the pressing process, it concentrates the pressing force on a local area of ​​the connected parts, driving the material of the connected parts to undergo plastic flow and embed into the groove portion 16, forming a force transmission and material flow path of "flange portion 11 → discharge section 17 → connected parts material → groove portion 164". The discharge section 17 pushes the material of the connected parts, and the groove section 16 accommodates the material that undergoes plastic flow due to the pushing. Together, they form an axial lock in addition to the interference fit lock provided by the first interference fit section 12 and the second interference fit section 13, further improving the connection reliability of the fastener 1.

[0026] Specifically, in the first to third embodiments, the fastener 1 is an integrally formed part, that is, the flange part 11, the rod body, the groove part 16 and the discharge part 17 can all be integrally formed from the same blank through processes such as cold forming, cold heading or cutting, rather than being assembled from multiple independent parts by welding, threaded connection or other methods. This reduces its manufacturing cost and helps to ensure its structural strength and dimensional accuracy.

[0027] Specifically, in this example, the fastener 1 body may be made of a high-strength material to provide reliable connection strength, such as heat-treated carbon steel.

[0028] Please see Figures 1 to 10 Specifically, the first embodiment discloses a conductive busbar connection system, including: First conductive busbar 2, the first conductive busbar 2 is provided with first mounting hole 21; Conductive bushing 3, wherein the conductive bushing 3 is provided with mating hole 31; The second conductive busbar 4, the second conductive busbar 4 being provided with a second mounting hole 41; and The fastener 1 for connecting the conductive busbar as described above; wherein, The rod of the fastener 1 passes through the first mounting hole 21 and the mating hole 31. The first mounting hole 21 is press-fitted with the first interference fit part 12. The mating hole 31 is press-fitted with the second interference fit part 13 and clearance fitted with the guide part 14. In the axial direction, the end face of the flange part 11 facing the rod abuts against the end face of the first conductive busbar 2 away from the conductive bushing 3. The fastening screw 5 includes a main body 51 and a head 52 connected to one axial end of the main body 51. The outer diameter of the head 52 is larger than the outer diameter of the main body 51. The main body 51 passes through the second mounting hole 41 and is screwed into the inner hole 15, so that the head 52 presses the second conductive busbar 4 against the conductive bushing 3 on the side away from the first conductive busbar 2, so that the conductive bushing 3 abuts against the first conductive busbar 2 and the second conductive busbar 4 respectively, so as to electrically conduct the first conductive busbar 2 and the second conductive busbar 4.

[0029] In the above configuration, the rod of the fastener 1 passes through the first mounting hole 21 and the mating hole 31. The first mounting hole 21 is press-fitted with the first interference fit part 12, and the mating hole 31 is press-fitted with the second interference fit part 13 and clearance-fitted with the guide part 14. That is, the first interference fit part 12 is pressed into the first mounting hole 21, and the second interference fit part 13 is pressed into the mating hole 31, generating radial friction to provide anti-torsional and anti-push forces. The guide part 14 slides freely in the mating hole 31 to provide guidance. The design of the guide part 14, the second interference fit part 13, the first interference fit part 12, and the flange part 11 with progressively increasing outer diameters allows each section to gradually enter the corresponding assembly hole during the press-fitting process. The resistance is gradually dispersed rather than concentrated instantaneously, thereby effectively reducing the overall press-fitting force and avoiding deformation or crushing of the low-rigidity copper or aluminum conductive bushing 3 due to concentrated press-fitting force. This allows the fastener 1 to be adapted to assembly scenarios with long conductive bushings 3. In the axial direction, the end face of the flange 11 facing the rod body abuts against the end face of the first conductive busbar 2 away from the conductive bushing 3 to prevent the fastener 1 from coming out.

[0030] The fastening screw 5 includes a main body 51 and a head 52. The outer diameter of the head 52 is larger than the outer diameter of the main body 51. The main body 51 passes through the second mounting hole 41 and is screwed into the inner hole 15. The fastening screw 5 is fixedly connected to the fastener 1 through threaded engagement. The head 52 presses the second conductive busbar 4 against the conductive bushing 3 on the side opposite to the first conductive busbar 2, so that the conductive bushing 3 abuts against the first conductive busbar 2 and the second conductive busbar 4 respectively, thereby electrically connecting the first conductive busbar 2 and the second conductive busbar 4, forming a current path of first conductive busbar 2 → conductive bushing 3 → second conductive busbar 4 (or vice versa). It should be understood that in this connection system, only the conductive bushing 3 serves as a conductive channel, and the fastener 1 and the fastening screw 5 only play a mechanical locking role. Thus, a reliable electrical connection and mechanical locking between the first conductive busbar 2 and the second conductive busbar 4 are achieved, completely replacing the welding connection method.

[0031] Specifically, in this embodiment, the outer diameter of the guide portion 14 is smaller than the inner diameter of the mating hole 31 to ensure a clearance fit between the guide portion 14 and the mating hole 31, thereby achieving the guiding function; the outer diameter of the first interference mating portion 12 is larger than the inner diameter of the first mounting hole 21 to ensure an interference fit between the first interference mating portion 12 and the first mounting hole 21, providing anti-torsion and anti-push capabilities; the outer diameter of the second interference mating portion 13 is larger than the inner diameter of the mating hole 31 to ensure an interference fit with the mating hole 31, while its outer diameter is smaller than the inner diameter of the first mounting hole 21 to ensure that it can pass smoothly through the first mounting hole 21 without interference. For example, the outer diameter of the guide portion 14 is 0.1 mm smaller than the inner diameter of the mating hole 31, the outer diameter of the first interference mating portion 12 is 0.3 mm larger than the inner diameter of the first mounting hole 21, and the outer diameter of the second interference mating portion 13 is 0.3 mm larger than the inner diameter of the mating hole 31 and slightly smaller than the inner diameter of the first mounting hole 21.

[0032] Specifically, in this embodiment, the radial interference of the first interference fit 12 and the second interference fit 13 is 0.5 mm, that is, the outer diameter of the first interference fit 12 is 0.5 mm larger than the inner diameter of the first mounting hole 21, and the outer diameter of the second interference fit 13 is 0.5 mm larger than the inner diameter of the mating hole. Of course, in other embodiments, the radial interference of the first interference fit 12 and the second interference fit 13 can also be approximately 0.2 mm to 0.7 mm, so that the outer diameter of the first interference fit 12 is 0.2 mm to 0.7 mm larger than the inner diameter of the first mounting hole 21, and the outer diameter of the second interference fit 13 is 0.2 mm to 0.7 mm larger than the inner diameter of the mating hole. The above-mentioned range of interference values ​​ensures that the two interference fits have sufficient interference with the corresponding holes to provide reliable anti-torsion and anti-push capabilities, while avoiding excessive pressing force or excessive compression of the conductive bushing 3 due to excessive interference. It should be noted that the above numerical range can be appropriately adjusted according to the specific material, wall thickness and required connection strength of the external connectors and external mating parts, and the tolerance range can be tightened according to the actual working conditions.

[0033] Specifically, in this embodiment, the mating hole 31 of the conductive bushing 3 is a straight hole, that is, the inner diameter of the mating hole 31 is constant along the axial direction, so as to achieve a clearance fit with the guide portion 14 while simultaneously having an interference fit with the second interference fit portion 13. And as... Figures 12 to 15As shown, in the third embodiment, unlike the first embodiment, the wall surface for forming the mating hole 31 includes a first inner peripheral wall 311 and a second inner peripheral wall 312. The inner diameter of the first inner peripheral wall 311 is larger than the inner diameter of the second inner peripheral wall 312, and the inner diameter of the second inner peripheral wall 312 is larger than the outer diameter of the main body 51 of the fastening screw 5. In other words, the mating hole 31 is a variable diameter hole, which is divided into two sections with different inner diameters along the axial direction: the first inner peripheral wall 311 forms the end of the mating hole 31 away from the second conductive busbar 4 (upper section) to have an interference fit with the second interference fit part 13 and a clearance fit with the guide part 14; the second inner peripheral wall 312 forms the end of the mating hole 31 close to the second conductive busbar 4 (lower section), and is located axially between the end of the rod body away from the flange part 11 and the end face of the second conductive busbar 4 facing the first conductive busbar 2, so that the main body 51 of the fastening screw 5 can pass through. Compared to a straight hole structure, the advantage of this variable diameter hole structure is that by extending the upper inner wall of the guide bushing radially inward (forming a second inner peripheral wall 312 with a smaller inner diameter), the wall thickness of the upper end of the conductive bushing 3 is increased, thereby increasing the contact area between the conductive bushing 3 and the second conductive busbar 4. This helps to reduce contact resistance, reduce heat generation, and improve conductivity. At the same time, the upper inner wall provides radial support to the main body 51 of the fastening screw 5, which also improves the stability of the threaded fit between the fastening screw 5 and the fastener 1.

[0034] Specifically, in this embodiment, the first conductive busbar 2, the second conductive busbar 4, and the conductive bushing 3 are all made of copper. Copper has excellent conductivity and high strength, making it more suitable for scenarios requiring high conductivity. Of course, in other embodiments, the first conductive busbar 2, the second conductive busbar 4, and the conductive bushing 3 can also be made of other conductive materials, such as aluminum, to leverage aluminum's low density and light weight, making it more suitable for new energy vehicle scenarios with high weight reduction requirements. The fastener 1 is preferably made of carbon steel through heat treatment to provide high connection strength, and the fastening screw 5 can also be made of carbon steel.

[0035] Specifically, in this embodiment, the fastener 1 is riveted to the first conductive busbar 2. That is, the fastener 1 is pressed into the first mounting hole 21 and the mating hole 31 by riveting, forming an interference fit between the first interference fit portion 12 and the first mounting hole 21, and between the second interference fit portion 13 and the mating hole 31, respectively, thereby achieving a fixed connection between the fastener 1 and the first conductive busbar 2 and the conductive bushing 3. After riveting, the flange portion 11 abuts against the surface of the first conductive busbar 2 facing away from the second conductive busbar 4, providing pull-out resistance. When the fastener 1 has a groove portion 16 and a discharge portion 17, the discharge portion 17 drives a portion of the material of the first conductive busbar 2 to flow and embed into the groove portion 16, forming additional axial locking. Riveting connection has advantages such as quick assembly, reliable connection, and no welding required, making it suitable for mass production scenarios.

[0036] Please see Figures 7 to 10 Specifically, in this embodiment, the first conductive busbar 2 and the conductive bushing 3 can be press-fitted onto the fastener 1 in two steps: like Figures 7 to 8 As shown, the first step is to press the fastener 1 separately into the first mounting hole 21 of the first conductive busbar 2, so that the first interference fit part 12 and the first mounting hole 21 form an interference fit, and the flange part 11 abuts against the surface of the first conductive busbar 2. like Figures 9 to 10 As shown, the second step is to insert the conductive bushing 3 from the end of the fastener 1 away from the flange 11 (at this time, the guide part 14 first enters the mating hole 31, and the coaxiality of the conductive bushing 3 and the fastener 1 is ensured by its clearance fit relationship). Then, the conductive bushing 3 is pushed towards the flange 11, so that the second interference fit part 13 is pressed into the mating hole 31 to form an interference fit, until the end face of the conductive bushing 3 facing the first conductive busbar 2 abuts against the end face of the first conductive busbar 2 facing the conductive bushing 3. Finally, the second conductive busbar 4 is locked by the fastening screw 5.

[0037] Please see Figure 11In the second embodiment, unlike the first embodiment, the first conductive busbar 2 and the conductive bushing 3 are directly press-fitted onto the fastener 1 in one step. More specifically, the first conductive busbar 2 and the conductive bushing 3 are first fitted onto the rod body from the guide portion 14 of the fastener 1 away from the flange portion 11. Due to the relationship between the outer diameter of each functional segment of the rod and the inner diameter of the first mounting hole 21 and the mating hole 31, at least the first conductive busbar 2 will remain at the end of the first interference mating portion 12 away from the flange portion 11, and the conductive bushing 3 will remain at the end of the second interference mating portion 13 away from the first interference mating portion 12. At this time, a pressing force is applied at once by the riveting device. During this process, an interference connection can be formed between the mating hole 31 of the conductive bushing 3 and the second interference mating portion 13, and an interference connection can be formed between the first mounting hole 21 and the first interference mating portion 12. Finally, the end face of the flange portion 11 facing the first conductive busbar 2 abuts against the first conductive busbar 2. After pressing, the second conductive busbar 4 can be tightened by the fastening screws 5, so that the end face of the second conductive busbar 4 facing the first conductive busbar 2 abuts against the end face of the conductive bushing 3 away from the first conductive busbar 2. This method has higher assembly efficiency and is more suitable for mass automated production scenarios. Since the outer diameters of the guide part 14, the second interference fit part 13, the first interference fit part 12, and the flange part 11 increase sequentially, each section enters the corresponding hole in sequence during the pressing process, and the resistance is gradually dispersed, resulting in a lower overall pressing force. Even if the pressing force needs to be transmitted through the copper or aluminum conductive bushing 3 with lower rigidity, it will not cause the conductive bushing 3 to be deformed or crushed, making the one-step installation method safe to implement.

[0038] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any changes, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fastener for connecting conductive busbars, characterized in that, include: Flange section; The rod body is axially connected to one end of the flange portion. From the end connected to the flange portion, it is provided with a first interference fit portion, a second interference fit portion, and a guide portion in sequence. The outer diameters of the guide portion, the second interference fit portion, the first interference fit portion, and the flange portion increase in sequence, and the difference between the outer diameter of the first interference fit portion and the outer diameter of the second interference fit portion is 0.5mm-1.0mm. An inner hole extends axially inward from one end of the rod body away from the flange, and a thread is formed on the inner wall of the inner hole.

2. The fastener for connecting conductive busbars according to claim 1, characterized in that, The first interference fit part and the second interference fit part are respectively one of straight knurling structure, oblique knurling structure or polygonal protrusion structure.

3. The fastener for connecting conductive busbars according to claim 1, characterized in that, It also includes a groove located axially between the flange and the rod, and the groove surrounds the outer periphery of the rod.

4. The fastener for connecting conductive busbars according to claim 3, characterized in that, It also includes a material discharge section, which is located between the flange section and the groove section to drive the material of the connected parts into the groove section during riveting; The outer diameter of the discharge section is smaller than the outer diameter of the flange section but larger than the outer diameter of the first interference fit section.

5. The fastener for connecting conductive busbars according to claim 1, characterized in that, The fastener is a one-piece molded part.

6. A conductive busbar connection system, characterized in that, include: A first conductive busbar, wherein the first conductive busbar is provided with a first mounting hole; A conductive bushing, wherein the conductive bushing is provided with a mating hole; A second conductive busbar, the second conductive busbar being provided with a second mounting hole; and Fasteners for conductive busbar connections as described in any one of claims 1 to 5; wherein, The fastener's rod passes through the first mounting hole and the mating hole. The first mounting hole is press-fitted with the first interference fit part. The mating hole is press-fitted with the second interference fit part and clearance-fitted with the guide part. In the axial direction, the end face of the flange part facing the rod part abuts against the end face of the first conductive busbar away from the conductive bushing. A fastening screw, comprising a main body and a head connected to one axial end of the main body, wherein the outer diameter of the head is larger than the outer diameter of the main body, wherein the main body passes through the second mounting hole and is screwed into the inner hole, so that the head presses the second conductive busbar against the conductive bushing on the side away from the first conductive busbar, thereby causing the conductive bushing to abut against the first conductive busbar and the second conductive busbar respectively, so as to electrically connect the first conductive busbar and the second conductive busbar.

7. The conductive busbar connection system according to claim 6, characterized in that, The outer diameter of the guide portion is smaller than the inner diameter of the mating hole; The outer diameter of the first interference fit is larger than the inner diameter of the first mounting hole; The outer diameter of the second interference fit part is larger than the inner diameter of the fit hole and smaller than the inner diameter of the first mounting hole.

8. The conductive busbar connection system according to claim 6, characterized in that, The mating hole of the conductive bushing is a straight hole; or, The wall surface for forming the mating hole includes a first inner peripheral wall and a second inner peripheral wall, wherein the inner diameter of the first inner peripheral wall is larger than the inner diameter of the second inner peripheral wall; and the inner diameter of the second inner peripheral wall is larger than the outer diameter of the body portion of the fastening screw; wherein... The first inner peripheral wall forms the end of the mating hole away from the second conductive busbar to have an interference fit with the second interference fit portion and a clearance fit with the guide portion; The second inner peripheral wall forms the mating hole near the end of the second conductive busbar, and is located axially between the end of the rod body away from the flange and the end face of the second conductive busbar facing the first conductive busbar, so that the main body of the fastening screw can pass through.

9. The conductive busbar connection system according to claim 6, characterized in that, The first conductive busbar, the second conductive busbar, and the conductive bushing are made of copper or aluminum, respectively.

10. The conductive busbar connection system according to claim 6, characterized in that, The fastener is press-fitted to the first conductive busbar.

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