CN111786227A

CN111786227A - Method for manufacturing bus bar by friction stir welding

Info

Publication number: CN111786227A
Application number: CN201910661950.1A
Authority: CN
Inventors: 金明壎; 徐宗德
Original assignee: Afa House Co ltd
Current assignee: Afa House Co ltd
Priority date: 2019-04-05
Filing date: 2019-07-22
Publication date: 2020-10-16
Also published as: KR102034012B1

Abstract

The present invention relates to a method for manufacturing a bus bar by friction stir welding, which can easily manufacture a bus bar by friction stir welding aluminum and copper. The method comprises the following steps: an extrusion step of extruding one first conductor and two second conductors into rectangular shapes, respectively; a disposing step of disposing the second conductors at both ends of the first conductor, respectively; and a bus bar forming step of forming a bus bar by friction stir welding between the first conductor and the second conductor, wherein the first conductor is aluminum and the second conductor is copper.

Description

Method for manufacturing bus bar by friction stir welding

Technical Field

The present invention relates to a method for manufacturing a bus bar by friction stir welding, and more particularly, to a method for manufacturing a bus bar by friction stir welding, which can easily manufacture a bus bar by friction stir welding aluminum and copper.

Background

Bus bars (Bus bars) are a medium for transmitting electric energy, and in the past, cables were mainly used, but Bus bars have recently been used as a substitute for cables due to their many advantages.

As can be seen from the structural comparison of the bus bar and the cable, the similarity is that both have a conductor and an insulator, but the bus bar has the greatest advantage that the same volume of conductor can transmit more electric energy. Therefore, as the merits of bus bars in large-capacity power distribution systems are known, the amount of bus bars used is rapidly increasing, and the demand for large buildings, large factories, power plants, subways, and the like, which require large-capacity electric energy, is rapidly increasing compared to the past, and bus bars are considered to be parts that are very suitable for modern large-capacity power transmission systems because of the trend of bus bars, safety, and low energy loss.

Korean patent No. 10-1844270 (granted on 03/27/2018) discloses a bus bar and a method for manufacturing the same, which is characterized by comprising: preparing a plurality of strip-shaped metal components for conducting electricity; bending the plurality of metal members only in a side surface direction which is a direction in which the thickness is thin, and bending the upper surface and the lower surface so that the upper surface and the lower surface are always kept flat even before and after the bending; welding the bent portions of the plurality of metal members; and a step of stacking the plurality of metal members and bonding the plurality of metal members so that the plurality of stacked metal members integrally operate in a state of being in close contact with each other, wherein the plurality of metal members are made of copper or aluminum.

Korean patent No. 10-1118098 (granted on date 13/02/2012) discloses a composite metal bus bar and an electrical device having the same. According to the disclosed technique, the composite metal bus bar is characterized by being composed of a double layer of an inner layer made of aluminum and an outer layer made of copper, in the form of square bars (bar) having a copper layer thickness on the long side that is less than the copper layer thickness on the short side, and a copper to aluminum weight ratio of 10: 90 to 30: 70.

as described above, the bus bar has been generally manufactured using copper or aluminum as a raw material, and copper is expensive and characteristically heavy, and thus there is a possibility that a problem may be caused in durability of the product.

On the contrary, aluminum, which is a cheap raw material, has a volume 2 times or more larger than that of copper because its conductivity is lower than that of copper, otherwise, it generates heat when it is electrified, thus causing a problem that a cooler is required depending on the use environment, and it is not suitable for heavy electric equipment or equipment with a capacity more than that because it has a high possibility that the aluminum raw material with a low melting point is melted by an arc which may be generated when it is electrified.

In addition, as described above, in the conventional composite metal bus bar, since poor bonding between aluminum and copper occurs or bonding between aluminum and copper is not strong, there is a problem that a bonded portion is cracked by external impact or the like, and thus, there is a disadvantage that a manufacturing process of the bus bar is complicated or maintenance cost is increased due to an increase in the bonding force between aluminum and copper.

Documents of the prior art

Patent document

Korean granted patent No. 10-1844270

Korean granted patent No. 10-1118098

Disclosure of Invention

Technical problem

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for manufacturing a bus bar by friction stir welding, which can easily manufacture a bus bar by friction stir welding aluminum and copper.

Technical scheme

In order to solve these problems, according to one feature of the present invention, there is provided a bus bar manufacturing method using friction stir welding, including: an extrusion step, wherein a first conductor and two second conductors are respectively extruded into a rectangular shape; a disposing step of disposing the second conductors at both ends of the first conductor in close contact with each other; and a bus bar forming step of forming a bus bar by friction stir welding between the first conductor and the second conductor, wherein the first conductor is aluminum and the second conductor is copper.

In one embodiment, the bus bar forming step includes: in the rotating process, a rotating welding tool of the friction stir welding machine is rotated; an insertion process of inserting the rotary bonding tool into a portion to which the first conductor and the second conductor are attached; a frictional heat generating process of generating frictional heat at a portion where the first conductor and the second conductor are brought into close contact with each other by the rotary bonding tool; and a welding process of advancing the rotary bonding tool to weld the first conductor and the second conductor.

In one embodiment, the method further comprises a reinforcing step after the bus bar forming step, wherein the friction stir welded portion of the bus bar is heated to be semi-molten and then cooled.

In one embodiment, the method further comprises an adhesive coating step before the disposing step, wherein a metal adhesive is coated on the attaching surface of the first conductor or the attaching surface of the second conductor.

In one embodiment, the first conductor has a plurality of protrusions formed on an abutting surface.

In one embodiment, the second electrical conductor has a plurality of slots formed in an abutting surface.

Effects of the invention

According to the present invention, since the bus bar is formed by friction stir welding copper on both ends of aluminum, the manufacturing process thereof is simple, and thus mass production is possible, the manufacturing cost is reduced, and a high-quality bus bar having a strong bonding force between aluminum and copper can be manufactured.

Further, since the bus bar is formed by combining aluminum and copper, it can be greatly reduced in weight, and thus it can be used for various transportation tools such as automobiles requiring light weight and rigidity, and has the effect of facilitating storage and transportation and improving workability.

Drawings

Fig. 1 is a flowchart illustrating a method of manufacturing a bus bar using friction stir welding according to a first embodiment of the present invention.

Fig. 2 is a flowchart illustrating a bus bar forming step in fig. 1.

Fig. 3 is a view illustrating a bus bar forming step in fig. 1.

Fig. 4 is a flowchart illustrating a method of manufacturing a bus bar using friction stir welding according to a second embodiment of the present invention.

Fig. 5 is a flowchart illustrating a method of manufacturing a bus bar using friction stir welding according to a third embodiment of the present invention.

Reference numerals

100: first conductor

200: second conductor

T: rotary welding tool

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the invention. However, the description of the present invention is merely for illustrative purposes and is intended to serve as a structural or functional description, and therefore the scope of the present invention should not be construed as limited by the embodiments set forth herein. That is, the embodiments can be variously modified and can have various modes, and therefore, the scope of the claims of the present invention should be understood to include equivalents capable of realizing the technical idea. Further, the purpose or effect presented in the present invention does not mean that a specific embodiment is all or only that effect, and therefore, it is not to be understood that the scope of the right of the present invention is limited by the specific embodiment.

On the other hand, the meanings of the terms described in the present invention should be understood as follows.

The terms "first", "second", and the like are used to distinguish one constituent element from another constituent element, and the scope of the claims should not be limited by these terms. For example, the first component can be named as the second component, and similarly, the second component can also be named as the first component.

When a component is referred to as being "connected" to another component, it is to be understood that the component may be directly connected to the other component or may have another component interposed therebetween. In contrast, when a component is referred to as being "directly connected" to another component, it is to be understood that no other component is present therebetween. On the other hand, other expressions such as "between" and "immediately between" or "adjacent to" and "directly adjacent to" for describing the relationship between the respective constituent elements are also to be interpreted similarly.

Unless the context clearly dictates otherwise, the expression in the singular is to be understood as including the expression in the plural, and it is to be understood that the terms "comprises" or "comprising" or the like are intended to specify the presence of the stated features, steps, acts, elements, components or combinations thereof, but does not preclude the presence or addition of one or more other features or numbers, steps, acts, elements, components or combinations thereof.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Each term defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with its meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

A method for manufacturing a bus bar by friction stir welding according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1, first, one first conductor 100 and two second conductors 200 are extruded in a rectangular shape using an extruder, respectively (S100).

In step S100, the first conductor 100 is aluminum and the second conductor 200 is copper.

In step S100, the length of the second conductor 200 can be formed to be greater than the length of the first conductor 100, and the thicknesses thereof can be formed to be the same.

Second conductors 200 are respectively disposed in close contact with both ends of the first conductor 100 pressed in the step S100 (S200).

In step S200, the second conductor 200, which is a copper material having relatively high electrical conductivity and a relatively high melting point, is provided only at both ends of the first conductor 100, which is a portion where electrical contact occurs, so that the performance of the bus bar can be improved and the weight can be greatly reduced.

Friction stir welding is performed between the first conductor 100 and the second conductor 200 disposed in the step S200 to form a bus bar (S300).

Friction Stir Welding (Friction Stir Welding) is solid phase Welding in which a Tool (Tool) having a special shape is inserted into a base material while being rotated, and frictional heat (temperature lower than the melting point of the base material) generated in the base material is utilized, and has excellent performance for joining lightweight nonferrous metals (Al, Cu, Ti, etc.).

The friction stir welded portion of the bus bar formed in step S300 is ground to be flat and smooth, so that the quality of the bus bar can be improved.

The bus bar formed at the step S300 can be pressed to have a predetermined shape (e.g., half-transverse n-shape) according to an installation place. At this time, the bus bar can be heated in advance to perform the extrusion work.

The second conductor 200, which is both ends of the bus bar formed in step S300, is pressed to form terminal holes for connecting the terminals.

In the method for manufacturing a bus bar by friction stir welding including the above-described steps, the first conductor 100 may have a plurality of protrusions on the contact surface, and the second conductor 200 may have a plurality of grooves on the contact surface at positions corresponding to the protrusions of the first conductor 100. Accordingly, when the first conductor 100 and the second conductor 200 are closely attached in the step S200, the protrusions and the grooves are coupled to each other, so that the looseness between the first conductor 100 and the second conductor 200 is minimized when friction stir welding is performed, and the coupling force between the first conductor 100 and the second conductor 200 can be further improved.

The method for manufacturing a bus bar using friction stir welding having the above-described steps forms a bus bar by friction stir welding the second conductor 200, which is copper, to both ends of the first conductor 100, which is aluminum, and simplifies the manufacturing process, thereby enabling mass production, reduction in manufacturing cost, and production of a high-quality bus bar having a strong coupling force.

Fig. 2 is a flowchart illustrating a bus bar forming step in fig. 1, and fig. 3 is a diagram illustrating the bus bar forming step in fig. 1.

Referring to fig. 2 and 3, first, the rotary tool T of the friction stir welding machine is rotated at a preset speed (S310).

In the step S310, the rotary welding tool T can be rotated at 1400-1600 RPM. When the rotation speed of the rotary bonding tool T is less than 1400RPM, abrasion may occur at the welding portion due to insufficient heat input, and when the rotation speed is more than 1600RPM, the temperature may sharply rise to cause defects.

The rotary jig T rotated in step S310 is inserted into a portion where the first conductor 100 and the second conductor 200 are in close contact with each other (S320).

In step S320, the rotary jig T can be inserted into a portion where the first conductor 100 and the second conductor 200 are in close contact with each other to a depth of approximately 1 to 2 mm.

In step S320, a pressurizing force is applied to the rotary bonding tool T at a pressure of 3000 to 5000N, and the rotary bonding tool T is inserted into a portion where the first conductor 100 and the second conductor 200 are in close contact with each other.

The rotary bonding tool T inserted in step S320 generates frictional heat at the portion where the first conductor 100 and the second conductor 200 are in close contact with each other (S330).

In step S330, the rotary bonding tool T is inserted into the portion where the first conductor 100 and the second conductor 200 are in close contact with each other, and the rotating state is maintained for 3 to 8 seconds to generate frictional heat, so that the first conductor 100 and the second conductor 200 can be smoothly welded to each other.

The rotary bonding tool T in step S330 is advanced to bond the first conductor 100 and the second conductor 200 (S340).

In the step S340, the rotary welding tool T can be moved forward at a moving speed of 200-300 mm/min. When the moving speed of the rotary bonding tool T is less than 200mm/min, the tensile strength of the bus bar is lowered, and when the moving speed is more than 300mm/min, heat input is insufficient due to an excessive conveying speed, and thus a defect may occur.

Referring to fig. 4, the method further includes a strengthening step (S400) after the step S300, wherein the friction stir welded portion of the bus bar is heated to be semi-melted and then cooled.

In step S400, the friction stir welded portion can be heated at a temperature of 500 to 650 ℃ for approximately 60 to 120 minutes by a high frequency heater or the like to be half-melted, and then cooled at a cooling rate of 40 ℃/S or less. Here, in the case where the heating temperature is less than 500 ℃, the bus bar exists in a solid state, and in the case where the heating temperature exceeds 650 ℃, it is completely melted into a liquid phase, and therefore, it is preferable to perform heating in a range between the temperatures.

Generally, when friction stir welding is performed, a hole of the rotary welding tool T remains at the end of the joint portion, and thus there is a problem that the end needs to be cut off or post-processed.

However, the method of manufacturing a bus bar using friction stir welding according to the above-described steps has an effect of saving material and solving troubles because the strength can be improved and the hole generated at the end of the bus bar is eliminated while the friction stir welded portion is semi-melted by performing the step S400, and thus the end of the bus bar does not need to be cut or post-processed.

Referring to fig. 5, before the step S200, a metal adhesive is applied to the adhesion surface of the first conductor 100 or the adhesion surface of the second conductor 200 (S500).

Here, the metal adhesive may be a conductive epoxy adhesive mixed with silver, and the adhesive force is not weakened even when heat is applied, and the bonding force between the first conductor 100 and the second conductor 200 can be further improved.

As described above, the embodiments of the present invention can be embodied not only by the above-described devices and/or operation methods but also by a program for realizing functions corresponding to the configurations of the embodiments of the present invention, a recording medium on which the program is recorded, and the like, and those skilled in the art can easily embody the embodiments based on the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the appended claims are also within the scope of the present invention.

Claims

1. A method of manufacturing a bus bar using friction stir welding, comprising:

an extrusion step, wherein a first conductor and two second conductors are respectively extruded into a rectangular shape;

a disposing step of disposing the second conductors at both ends of the first conductor in close contact with each other; and the number of the first and second groups,

a bus bar forming step of forming a bus bar by friction stir welding between the first conductor and the second conductor,

wherein the first electrical conductor is aluminum and the second electrical conductor is copper.

2. The manufacturing method of a bus bar using friction stir welding according to claim 1,

the bus bar forming step includes:

in the rotating process, a rotating welding tool of the friction stir welding machine is rotated;

an insertion process of inserting the rotary bonding tool into a portion to which the first conductor and the second conductor are attached;

a frictional heat generating process of generating frictional heat at a portion where the first conductor and the second conductor are brought into close contact with each other by the rotary bonding tool; and the number of the first and second groups,

and a welding step of advancing the rotary bonding tool to weld the first conductor and the second conductor.

3. The manufacturing method of a bus bar using friction stir welding according to claim 1,

further comprising a strengthening step after the bus bar forming step, heating the friction stir welded portion of the bus bar to semi-melt it, and then cooling it.

4. The manufacturing method of a bus bar using friction stir welding according to claim 1,

the method further comprises an adhesive coating step before the arranging step, wherein a metal adhesive is coated on the attaching surface of the first conductor or the attaching surface of the second conductor.

5. The manufacturing method of a bus bar using friction stir welding according to claim 1,

the first conductor has a plurality of protrusions formed on a surface thereof to be in close contact with the first conductor.