Aluminum bar switching structure
By using friction welding or torque ultrasonic welding with copper bushings at the aluminum row transition points, the problems of electrochemical corrosion, high connection resistance and stress relaxation in aluminum-to-copper connections are solved, and a reliable aluminum-to-copper connection solution is realized. Suitable for long-term high current working conditions of charging lines.
Patent Information
- Application Number
- CN202421100251.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-20
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-05-20
AI Technical Summary
The existing aluminum-copper connection solution at the aluminum strip adapter has problems such as electrochemical corrosion, large connection resistance and loose stress, which cannot meet the long-term and large current conditions during the charging process.
The aluminum row and the copper bushing are connected by friction welding or torque ultrasonic welding. The copper bushing includes a small diameter section and a large diameter section, and the step surface is designed to increase the welding contact area.
It effectively improves the electrochemical corrosion, high connection resistance and stress relaxation problems at the copper-aluminum connection, and provides a reliable aluminum-to-copper connection solution that can meet long-term high-current charging conditions.
Smart Images
Figure CN222380880U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of aluminum bar connection, in particular to an aluminum bar transfer structure. Background Art
[0002] At present, aluminum busbar wiring harnesses have been successfully applied in automobiles, but the connection scheme at the aluminum busbar transition is still difficult. Because there are problems such as electrochemical corrosion, large contact resistance, and different thermal expansion coefficients between aluminum and copper, a reliable aluminum-to-copper solution needs to be found at the aluminum busbar transition to achieve copper-to-copper connection between the aluminum busbar and the car body. The solutions currently used in the industry are: 1. Silver plating on the aluminum busbar and then ultrasonically welding the copper sheet; 2. Riveting the aluminum busbar to the copper sleeve.
[0003] The existing technology has the following disadvantages: In the first method, there may be gaps and stress relaxation problems on the copper-aluminum welding surface, and electrochemical corrosion may occur over time. At the same time, due to the energy limitation of the welding equipment, the specifications of the welded aluminum bars are also limited. When the thickness of the aluminum bar is relatively small, the equipment welding energy is sufficient, and ultrasonic welding is reliable, but for the aluminum bar specifications are larger, the welding is not thorough and the connection strength is low; the second method is a cold connection. Due to the different thermal expansion coefficients of copper and aluminum, the hot and cold shocks during the charging and discharging process are likely to form gaps or holes at the connection interface, resulting in increased resistance and temperature rise. In addition, due to the potential difference between copper and aluminum, electrochemical corrosion is likely to occur.
[0004] In summary, the current aluminum-to-copper solution adopted at the aluminum busbar transition has problems such as large connection resistance, electrochemical corrosion, and stress relaxation, and cannot meet the repeated long-term high current conditions during the charging process. Therefore, if the aluminum busbar is to be used more reliably and safely, a reliable aluminum-to-copper solution at the connection is still a key issue that needs to be solved. Utility Model Content
[0005] In view of the deficiencies in the above-mentioned background technology, the utility model proposes an aluminum busbar transfer structure, provides a reliable aluminum-to-copper solution, and solves the technical problems of electrochemical corrosion, high connection resistance and stress relaxation of the aluminum-to-copper connection.
[0006] The technical solution of this application is:
[0007] An aluminum bar transfer structure comprises an aluminum bar provided with a mounting hole, wherein the aluminum bar is connected to a copper bushing by friction welding or torque ultrasonic welding, wherein the copper bushing comprises a connected small diameter section and a large diameter section, wherein a step surface is formed between the large diameter section and the small diameter section; when friction welding is performed, friction welding is performed between the outer ring surface of the small diameter section and the mounting hole, and between the step surface and the bottom surface of the aluminum bar; when torque ultrasonic welding is performed, torque ultrasonic welding is performed between the step surface and the bottom surface.
[0008] The aluminum-to-copper connection structure provided by the technical solution rotates the copper bushing and applies pressure to the aluminum bar, or rotates the aluminum bar and applies pressure to the copper bushing, connects the small diameter section of the copper bushing in the mounting hole, and connects the step surface between the large diameter section and the small diameter section of the copper bushing to the bottom surface of the aluminum bar. During friction welding, the outer ring surface of the small diameter section is welded to the mounting hole, and the step surface is welded to the bottom surface of the aluminum bar; during torque ultrasonic welding, the outer ring surface of the small diameter section is plugged into the mounting hole, and the step surface is welded to the bottom surface of the aluminum bar.
[0009] Preferably, the mounting hole is a through hole, and the height of the outer ring surface is greater than the height of the mounting hole. After welding, the height of the outer ring surface needs to be higher than the height of the aluminum bar to ensure that the aluminum bar is still connected to the busbar or other connectors in the later stage.
[0010] Preferably, the large diameter section is arranged in the middle of the small diameter section, and the height of the outer ring surface of the small diameter section connected to one end of the aluminum bar is greater than the height of the mounting hole. Both ends of the copper bushing are arranged as small diameter sections, which can guide the copper connector plugged into the inner cavity of the copper bushing. The middle is the large diameter section. After the copper bushing is connected to the aluminum bar, the small diameter sections at both ends should be higher than the aluminum bar.
[0011] Preferably, when friction welding is performed, the mounting hole and the outer ring surface have an interference fit, and when torque ultrasonic welding is performed, the mounting hole and the outer ring surface have a clearance fit. During friction welding, the mounting hole and the outer ring surface are ensured to be melt-welded; during torque ultrasonic welding, the outer ring surface of the copper bushing is inserted into the mounting hole of the copper busbar before welding.
[0012] Preferably, there are several mounting holes, each of which is arranged at one end or / and both ends or / and the middle of the aluminum bar, and the distance between two adjacent mounting holes is not less than 2 times the diameter of the mounting hole. The position of the mounting holes is set as required, and a distance of 2 times the diameter is left between adjacent mounting holes to avoid deformation of the aluminum bar surface during stamping, which affects the tightness of the connection between the step surface of the copper bushing and the surface of the aluminum bar.
[0013] Preferably, the ratio of the diameter of the mounting hole to the minimum width of the aluminum bar is less than or equal to 1:2. A certain distance should be left between the mounting hole and the edge of the aluminum bar to avoid deformation of the aluminum bar during punching.
[0014] Preferably, the ratio of the diameter of the large diameter section to the diameter of the small diameter section is 1: 3. The step surface between the large diameter section and the small diameter section is in full contact with the surface of the aluminum bar, increasing the contact area of welding.
[0015] Preferably, the wall thickness of the copper bushing is at least 1.5 mm. The copper bushing should have a certain strength to avoid deformation of the copper bushing during welding, thereby causing a connection gap.
[0016] Preferably, the end of the small diameter section of the copper bushing is provided with a chamfer, which can prevent the tip of the small diameter section from damaging the copper wire or the copper connector.
[0017] Preferably, the cross-sectional shape of the inner cavity of the copper bushing is circular, elliptical or regular polygonal. The inner cavity of the copper bushing is interference-connected with the copper connector, and the cross-sectional shape of the copper connector can be circular, elliptical or regular polygonal.
[0018] Compared with the prior art, the technical solution disclosed in the utility model has the following beneficial effects:
[0019] The aluminum-to-copper connection method of the utility model can well meet the long-term high-current charging conditions of the charging cable, and improves the connection problems of easy electrochemical corrosion, high connection resistance and stress relaxation at the copper-aluminum connection. The aluminum-to-copper connection method of the utility model is reliable and not easy to loosen. It can not only be used as a charging harness, but also can be used for the connection of other parts. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present utility model, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 This is a schematic diagram of the split aluminum bar transfer structure of the utility model;
[0022] Figure 2 This is a schematic diagram of the assembly of the aluminum bar transfer structure of the utility model;
[0023] Figure 3 It is an assembly schematic diagram of embodiment 2 of the utility model.
[0024] Description of Figure Numbers:
[0025] 1 aluminum bar, 101 mounting hole, 102 bottom surface, 103 top surface, 2 copper bushing, 201 outer ring surface, 202 step surface, 203 connecting end surface. DETAILED DESCRIPTION
[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the core concept of the utility model and the following embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0027] Embodiment 1, an aluminum bar transfer structure, such as Figures 1 to 3As shown, it includes an aluminum bar 1 provided with a mounting hole 101, and the aluminum bar 1 is connected to the copper bushing 2 by friction welding or torque ultrasonic welding. The copper bushing 2 includes a connected small diameter section and a large diameter section, and a step surface 202 is formed between the large diameter section and the small diameter section. When friction welding is performed, friction welding is performed between the outer annular surface 201 of the small diameter section and the mounting hole 101, and between the step surface 202 and the bottom surface 102 of the aluminum bar 1; when torque ultrasonic welding is performed, torque ultrasonic welding is performed between the step surface 202 and the bottom surface 102.
[0028] The aluminum-to-copper connection structure provided by the technical solution allows the copper bushing 2 to rotate and apply pressure to the aluminum bar 1, or allows the aluminum bar 1 to rotate and apply pressure to the copper bushing 2, connects the small diameter section of the copper bushing 2 in the mounting hole 101, and connects the step surface 202 between the large diameter section and the small diameter section of the copper bushing 2 to the bottom surface 102 of the aluminum bar 1. During friction welding, the outer ring surface 201 of the small diameter section is welded to the mounting hole 101, and the step surface 202 is welded to the bottom surface 102 of the aluminum bar 1, which increases the welding area, reduces the connection gap between the copper bushing 2 and the aluminum bar 1, and enhances the electrical performance; during torque ultrasonic welding, the outer ring surface 201 of the small diameter section is plugged into the mounting hole 101, and the step surface 202 is welded to the bottom surface 102 of the aluminum bar 1, which improves the processing efficiency on the basis of reliable connection.
[0029] Embodiment 2, based on embodiment 1, is an aluminum busbar transfer structure, wherein the mounting hole 101 is a through hole, and the height of the outer ring surface 201 is greater than the height of the mounting hole 101. The height of the outer ring surface 201 needs to be higher than the height of the aluminum busbar 1, so that the connection end surface 203 of the copper bushing 2 protrudes from the mounting hole 101 after welding, so as to ensure that the aluminum busbar 1 is still connected to the busbar or other connectors in the later stage.
[0030] Embodiment 3, based on Embodiment 1, an aluminum bar transfer structure, wherein the large diameter section is arranged in the middle of the small diameter section, and the height of the outer ring surface 201 of the small diameter section connecting one end of the aluminum bar 1 is greater than the height of the mounting hole 101. Both ends of the copper bushing 2 are arranged as small diameter sections, which can guide the copper connector plugged into the inner cavity of the copper bushing 2. The middle is the large diameter section. After the copper bushing 2 is connected to the aluminum bar 1, the small diameter sections at both ends should be higher than the aluminum bar 1 to ensure that the aluminum bar 1 is still connected to the busbar or other connectors in the later stage.
[0031] Embodiment 4, based on any one of embodiments 1-3, an aluminum busbar transfer structure, when friction welding is performed, the mounting hole 101 and the outer ring surface 201 are interference fit, and when torque ultrasonic welding is performed, the mounting hole 101 and the outer ring surface 201 are clearance fit. During friction welding, the mounting hole 101 and the outer ring surface 201 are ensured to be melt welded; during torque ultrasonic welding, the outer ring surface 201 of the copper bushing 2 is inserted into the mounting hole 101 of the copper busbar 1, and then welding is performed, so as to avoid the problem of large connection resistance and electrochemical corrosion caused by the gap between the mounting hole 101 and the outer ring surface 201.
[0032] When friction welding is performed, the diameter of the mounting hole 101 is slightly smaller than the diameter of the outer ring surface 201, and the mounting hole 101 and the outer ring surface 201 are welded together by fusion; when torque ultrasonic welding is performed, the diameter of the mounting hole 101 is slightly larger than the diameter of the outer ring surface 201, and the outer ring surface 201 is inserted into the mounting hole 101 to form a clearance fit.
[0033] Embodiment 5, based on embodiment 4, an aluminum bar transfer structure, wherein a plurality of mounting holes 101 are provided, each mounting hole 101 is provided at one end or / and both ends or / and the middle of the aluminum bar 1, and the distance between two adjacent mounting holes 101 is not less than 2 times the diameter of the mounting hole 101. The position of the mounting holes 101 is set as required, and a distance of 2 times the diameter is left between adjacent mounting holes 101 to avoid deformation of the surface of the aluminum bar 1 during stamping, resulting in a gap between the step surface 202 of the copper bushing 2 and the bottom surface 102 of the aluminum bar 1, affecting the conductive performance.
[0034] Embodiment 6, based on embodiment 5, an aluminum bar transfer structure, wherein the ratio of the diameter of the mounting hole 101 to the minimum width of the aluminum bar 1 is less than or equal to 1:2. The mounting hole 101 is obtained by punching the aluminum bar 1, and a certain distance should be left between the mounting hole 101 and the edge of the aluminum bar 1 to avoid deformation of the aluminum bar 1 during punching.
[0035] Embodiment 7, based on any one of embodiments 1-3, an aluminum bar transfer structure, wherein the ratio of the diameter of the large diameter section to the diameter of the small diameter section is 1:3. Under the premise of easy processing, the step surface 202 between the large diameter section and the small diameter section should be in full contact with the bottom surface 102 of the aluminum bar 1, and the large diameter section increases the contact area of the welding while limiting the small diameter end, making the welding more firm.
[0036] Embodiment 8, based on any one of embodiments 1-3, an aluminum busbar transfer structure, wherein the wall thickness of the copper bushing 2 is at least 1.5 mm. The copper bushing 2 should have a certain strength to avoid deformation of the inner cavity of the copper bushing 2 due to the welding heat during the welding process due to the wall thickness being too thin, which makes it difficult or even impossible to connect the copper wire or copper connector to the inner cavity of the copper bushing 2 in the later stage.
[0037] Embodiment 9, based on any one of embodiments 1-3, an aluminum busbar transfer structure, wherein the end of the small diameter section of the copper bushing 2 is provided with a chamfer. The chamfer can avoid sharp points, and when the copper wire or the copper connector is connected to the inner cavity of the copper bushing 2, the sharp points can avoid damage to the copper wire or the copper connector.
[0038] Embodiment 10, based on any one of embodiments 1-3, an aluminum bar transfer structure, wherein the cross-sectional shape of the inner cavity of the copper bushing 2 is circular, elliptical or regular polygonal. The inner cavity of the copper bushing 2 is interference-connected with the copper connector, and the cross-section of the copper connector can be circular, elliptical or regular polygonal.
[0039] When embodiment 10 is implemented, when friction welding is used, its main steps are as follows:
[0040] Step 1: Punch the mounting hole 101 of the aluminum bar 1. The diameter of the mounting hole 101 is slightly smaller than the diameter of the small diameter section of the copper bushing 2 to ensure that the outer ring surface 201 of the copper bushing 2 and the aluminum bar 1 are in full contact during the friction welding process;
[0041] Step 2: The aluminum bar 1 and the copper bushing 2 are subjected to rotational friction welding. During the welding process, the aluminum bar 1 is fixed by a clamping tool, and the copper bushing 2 rotates at high speed and pressurizes and feeds the aluminum bar 1 to complete the friction welding;
[0042] Step 3: The welding contact surfaces of the copper bushing 2 and the aluminum row 1 are the outer ring surface 201 and the step surface 202;
[0043] Step 4: After welding, the height of the connection end surface 203 must be higher than the height of the top surface 102 to ensure that the aluminum bar 1 and the busbar are still connected by copper to copper in the later stage.
[0044] When Example 10 is implemented, when torque ultrasonic welding is used, its main steps are as follows:
[0045] Step 1: Punch the mounting hole 101 of the aluminum bar 1. The diameter of the mounting hole 101 is slightly larger than the diameter of the small diameter section of the copper bushing 2 to ensure that the outer ring surface 201 of the copper bushing 2 and the aluminum bar 1 are in full contact during the torque ultrasonic welding process;
[0046] Step 2: The aluminum bar 1 and the copper bushing 2 are subjected to torque ultrasonic welding. The torque ultrasonic welding utilizes a relative rotating mechanism. The aluminum bar 1 is fixed by a clamping fixture, and the copper bushing 2 rotates at high speed. Alternatively, the copper bushing 2 is fixed by a clamping fixture, and the aluminum bar 1 rotates at high speed. The welding speed, torque and angle are adjusted.
[0047] Step 3: The welding contact surface between the copper bushing 2 and the aluminum bar 1 is a step surface 202;
[0048] Step 4: After welding, the height of the connection end surface 203 must be higher than the height of the top surface 102 to ensure that the aluminum bar 1 and the busbar are still connected by copper to copper in the later stage.
[0049] The parts not described in detail in the present invention are all conventional technical means known to those skilled in the art.
[0050] The above content shows and describes the basic principle, main features and beneficial effects of the utility model. The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. An aluminum bar transfer structure, characterized in that: The invention comprises an aluminum bar (1) provided with a mounting hole (101), wherein the aluminum bar (1) is connected to a copper bushing (2) by friction welding or torque ultrasonic welding, wherein the copper bushing (2) comprises a small diameter section and a large diameter section connected to each other, and a step surface (202) is formed between the large diameter section and the small diameter section; when friction welding is performed, friction welding is performed between the outer annular surface (201) of the small diameter section and the mounting hole (101), and between the step surface (202) and the bottom surface (102) of the aluminum bar (1); when torque ultrasonic welding is performed, torque ultrasonic welding is performed between the step surface (202) and the bottom surface (102).
2. The aluminum bar transfer structure according to claim 1, characterized in that: The mounting hole (101) is a through hole, and the height of the outer annular surface (201) is greater than the height of the mounting hole (101).
3. The aluminum bar transfer structure according to claim 1, characterized in that: The large diameter section is arranged in the middle of the small diameter section, and the height of the outer annular surface (201) of the small diameter section connected to one end of the aluminum bar (1) is greater than the height of the mounting hole (101).
4. The aluminum bar transfer structure according to any one of claims 1 to 3, characterized in that: When friction welding is performed, the mounting hole (101) and the outer annular surface (201) are in interference fit, and when torque ultrasonic welding is performed, the mounting hole (101) and the outer annular surface (201) are in clearance fit.
5. The aluminum bar transfer structure according to claim 4, characterized in that: A plurality of mounting holes (101) are provided, each mounting hole (101) being provided at one end or / and both ends or / and the middle of the aluminum bar (1), and the distance between two adjacent mounting holes (101) is not less than twice the diameter of the mounting hole (101).
6. The aluminum bar transfer structure according to claim 5, characterized in that: The ratio of the diameter of the mounting hole (101) to the minimum width of the aluminum bar (1) is less than or equal to 1:
2.
7. The aluminum bar transfer structure according to any one of claims 1 to 3, characterized in that: The ratio of the diameter of the large diameter section to the diameter of the small diameter section is 1:
3.
8. The aluminum bar transfer structure according to any one of claims 1 to 3, characterized in that: The wall thickness of the copper bushing (2) is at least 1.5 mm.
9. The aluminum bar transfer structure according to any one of claims 1 to 3, characterized in that: The end of the small diameter section of the copper bushing (2) is provided with a chamfer.
10. The aluminum bar transfer structure according to any one of claims 1 to 3, characterized in that: The cross-sectional shape of the inner cavity of the copper bushing (2) is circular, elliptical or regular polygonal.