Method for joining copper wire

Abstract

To provide a method for joining copper wires enabling reduction in electric energy for welding and a space for welding.SOLUTION: A method for joining copper wires comprises: placing mixed powder of oxidation-reduction material (aluminum 13 and copper oxide 14) between a first copper wire 11 and a second copper wire 12 to be joined; bringing a first rhenium electrode 15 into contact with the first copper wire 11; bringing a second rhenium electrode 16 into contact with the second copper wire 12; and passing an electric current between the first rhenium electrode 15 and the second rhenium electrode 16. The first rhenium electrode 15 and the second rhenium electrode 16 having high heat resistance and low electrical resistance are used, the one having high electrical resistance higher than that of copper is placed on a part to be welded, heat generation is preferentially performed, and further a thermit reaction is utilized.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for joining copper wires. [Background technology]

[0002] Patent Document 1 describes a welding method in which aluminum plates are sandwiched between two pieces of material and thermite welding is performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3515592 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the welding method of Patent Document 1 is a method for welding aluminum to aluminum. Here, when welding copper wires together, it is more difficult to weld copper wires than aluminum wires.

[0005] Specifically, copper has lower electrical resistance than aluminum, so it does not generate heat as easily. Furthermore, copper has higher thermal conductivity than aluminum, so heat is easily transferred to the surroundings. And because copper has a higher melting point than aluminum, it needs to be heated to a higher temperature than aluminum in order to weld it.

[0006] As a result, there is a problem that welding copper is more difficult than welding aluminum, since other surrounding materials melt when welding copper. [Means for solving the problem]

[0007] In one embodiment of a method for joining copper wires, a mixed powder of an oxidation-reduction material is placed between a first copper wire and a second copper wire to be joined, a first rhenium electrode is brought into contact with the first copper wire, a second rhenium electrode is brought into contact with the second copper wire, and a current is passed between the first rhenium electrode and the second rhenium electrode. Effect of the Invention

[0008] According to the copper wire joining method of the present disclosure, the amount of electricity required for welding and the space required for welding can be reduced. [Brief description of the drawings]

[0009] [Figure 1] 4 is a schematic diagram showing the start of welding in the copper wire joining method according to the first embodiment. [Diagram 2] 4 is a schematic diagram showing a welding process in the copper wire joining method according to the first embodiment. [Diagram 3] 4 is a schematic diagram showing a state where welding is completed in the copper wire joining method according to the first embodiment. [Figure 4] 13 is a schematic diagram showing a state where welding is started in a copper wire joining method according to another embodiment. [Diagram 5] 13 is a schematic diagram showing a state where welding is started in a copper wire joining method according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First embodiment Hereinafter, the embodiments of the present invention will be described with reference to the drawings. A schematic diagram showing the start of welding in the copper wire joining method according to the first embodiment. In FIG. 1, a mixed powder of aluminum 13 and copper oxide 14 (i.e., an oxidation-reduction material) is placed between a first copper wire 11 and a second copper wire 12 to be joined. Then, a first rhenium electrode 15 is brought into contact with the first copper wire 11, and a second rhenium electrode 16 is brought into contact with the second copper wire 12. Then, a current is passed between the first rhenium electrode 15 and the second rhenium electrode 16. Here, the mixed powder of aluminum 13 and copper oxide 14 generates heat because it has a higher electrical resistance than rhenium and copper.

[0011] This heat generation causes the mixed powder of aluminum oxide 13 as an oxidizing agent and copper oxide 14 as a reducing agent to undergo the Temirut reaction, in which oxidation and reduction occur simultaneously. The oxidizing agent and reducing agent can be set arbitrarily depending on the base material to be joined. Figure 2 is a schematic diagram showing the copper wire joining method according to the first embodiment during welding.

[0012] The thermite reaction of copper generates heat according to the following reaction: 2Al+3Cu0→Al2O3+3Cu+reaction heat

[0013] This reaction heat generates heat at the joint between the first copper wire 11 and the second copper wire 12, melting the first copper wire 11 and the second copper wire 12. The heat is then transmitted throughout the first copper wire 11 and the second copper wire 12, causing the temperature of the joint between the first copper wire 11 and the second copper wire 12 to drop.

[0014] Fig. 3 is a schematic diagram showing the completion of welding in the copper wire joining method according to the first embodiment. As shown in Fig. 3, the first copper wire 11 and the second copper wire 12 are joined by reduced copper 31. Note that although the copper 31 contains aluminum oxide 32, the current flows through areas of lower resistance, and therefore flows through the area of ​​reduced copper rather than aluminum oxide, so the electrical resistance between the first copper wire 11 and the second copper wire 12 is low.

[0015] Thus, according to the copper wire joining method of embodiment 1, the rhenium used for the electrode is a material that has higher heat resistance and lower electrical resistance than the copper to be welded, so that a good thermite reaction can be achieved.

[0016] Spot welding is also less expensive than arc welding. Spot welding is a joining method in which the part to be welded, which has a higher electrical resistance than the electrode, melts when electricity is passed through it. In other words, the part to be welded must have a higher electrical resistance than the electrode and a lower melting point than the electrode. Therefore, the copper electrodes commonly used in spot welding cannot be used to spot weld copper.

[0017] In the method of joining copper wire in this embodiment, a rhenium electrode with high heat resistance and low resistance is used, and a material with higher electrical resistance than copper is placed at the weld, which generates heat preferentially, and furthermore, the thermite reaction is utilized, so that the powder generates high temperatures, which can save on electricity costs.

[0018] The present invention is not limited to the above embodiment, and can be modified as appropriate without departing from the spirit of the present invention. For example, as shown in Fig. 4, copper wires may be welded in a shape that joins them. Fig. 4 is a schematic diagram showing the start of welding in a method for joining copper wires according to another embodiment. In Fig. 4, the same components as those in Fig. 1 are assigned the same numbers, and the description thereof will be omitted.

[0019] The copper wire joining method of the present embodiment is suitable for the connection parts of distributed winding motors.

[0020] In distributed winding motors, the joints (coil ends) of the copper wire coil protrude, taking up space in the vehicle. However, by applying the copper wire joining method of this embodiment, welding can be performed with reduced heat generation, making it possible to shorten the coil ends.

[0021] In addition, the gist of the present disclosure is the welding of copper wires, and it is applicable to the welding of copper wires in general. Therefore, it may be used for the joint of the busbar part, and the structure of the motor may be changed. For example, it may be used for the copper wire joint of a concentrated winding motor, and it is also possible to use it in the same way for not only an IPM (Interior Permanent Magnet) motor but also an IM (Induction Motor) motor, which requires the joining of copper wires. The joint shape of the copper wire is not limited to only a lap joint. For example, it is possible to weld the joint by holding powder at the joint part. In this way, it is not limited to the joint shape. FIG. 5 is a schematic diagram showing the start of welding of a copper wire joining method according to another embodiment. In FIG. 5, the same components as those in FIG. 1 are given the same numbers, and the explanation is omitted. However, since it is difficult to hold the powder as it is, a viscous substance 51 may be mixed in as in brazing welding. In addition, the metal oxide used in the thermite reaction may be a metal oxide other than aluminum. For example, it may be an oxide of a metal such as Zn or Sn. [Explanation of symbols]

[0022] 11, 12 copper wire 13. Aluminum 14 Copper Oxide 15, 16 Rhenium electrodes 31 Copper 32 Aluminum Oxide 51 Substance

Claims

[Claim 1] A mixed powder of an oxidation-reduction material is placed between the first copper wire and the second copper wire to be joined; a first rhenium electrode abutting the first copper wire and a second rhenium electrode abutting the second copper wire; A method of joining copper wires comprising passing a current between the first rhenium electrode and the second rhenium electrode.

Images