JPS5854915B2 - Connection method between aluminum sheet and aluminum ribbon conductor - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a foil-wound coil formed by winding an aluminum sheet,
The present invention relates to a method of connecting an outlet conductor led out from this coil.

As the lead-out conductor led out from the foil-wound coil, a relatively thin ribbon-shaped conductor is usually used because it is easy to assemble.

The lead conductor is connected to the aluminum sheet at the beginning and end of the coil, and since the aluminum sheet and the lead conductor are connected during the coil winding process, cold pressure welding is widely used because of its good workability.

As shown in FIGS. 1 and 2, cold welding is carried out by placing a material 1 to be welded, which is made by overlapping an Al □ sheet 1a and an Al □ ribbon-shaped lead conductor 1b, into an oval-shaped upper die 2 having the same shape. This is a method in which the material is sandwiched and pressurized by a lower die 3 having the following characteristics.

Conventionally, this type of die is explained by taking the lower die 3 as an example.As shown in FIG.
3a and the base 13b are slightly rounded, and the side surface 13c of the projection 3a is machined with an appropriate draft angle.

When such convex dies 2 and 3 are used to press the aluminum sheet 1a and the material 1 to be pressure-welded of the aluminum ribbon-shaped lead conductor 1b, the aluminum material is transferred to the process shown in FIG.
Each protrusion 2a, 3 of the upper die 2 and the lower die 3
The tip portions 12a and 13a of the pressurized material 1 are sandwiched and compressed, and a tensile force is applied to the surface of the material 1 to be pressed, as shown in the opening in FIG. deforms with a radius of curvature.

As the compression progresses further, the portions of the press-welded material 1 sandwiched between the convex die protrusions 2a and 3a undergo plastic flow.

This phenomenon mainly concentrates on the long side side surfaces of each convex die protrusion 2a, 3a, and therefore the deformed portion of the press-welded material 1 gradually comes into close contact with the long side side surface of each convex die protrusion 2a, 3a. It turns out.

On the other hand, since the plastic flow of the welded material 1 toward the short side of each convex die protrusion 2a, 3a is small, the portion of the welded material 1 facing the short side side of the protrusion 2a, 3a is compressed. Even if it changes as the curve progresses, it does not come into close contact with the side surfaces of the protrusions 2a and 3a like the parts facing the long sides, but instead forms a rounded deformation with a large radius of curvature, as shown in Fig. 3C. .

Therefore, the base 12c of each convex die protrusion 2a, 3a,
A gap A is created between 13c and the deformed portion of the press-welded material 1.

This is because the plastic flow of the welded material occurs in the direction of the shortest flow distance.

Furthermore, during pressure welding, sliding friction occurs between each convex die protrusion 2a, 3a and the surface of the material 1 to be pressure welded.

Due to this sliding friction, fine powder particles are generated on the surface of the pressure-welded material 1, peeled off, and deposited in the above-mentioned gap A.

This is particularly noticeable when the pressure welding material 1 is aluminum.

Therefore, it is necessary to apply lubricating oil or the like to the surface of each convex die protrusion 2a, 3a, and to strictly control the degree of wear of each convex die protrusion 2a, 3a.

However, even a well-controlled convex die may suddenly wear out rapidly due to certain reasons.

If you continue the cold welding work in this condition, the above-mentioned void A will be formed.
The fine powder pieces deposited on the wafer are pressed together by the pressure during compression and become small pieces that adhere closely to the bases 12c and 13c of the respective convex die protrusions 2a and 3a.

The pieces that are in close contact with the bases 12c and 13c of the protrusions 2a and 3a fall off from the respective convex dies 2 and 3 due to some kind of impact or biting of the convex dies 2 and 3, and this pieces fall between the convex dies 2 and 3 and the material 1 to be welded under pressure. They may encourage biting, or they may get mixed into the insulation during coil winding, causing interlayer short circuits.

Therefore, it is necessary to constantly maintain the die surface and keep it clean, which makes it impossible to perform pressure welding and coil winding in a continuous process, which is a bottleneck in manufacturing.

The present invention has been made to solve the above-mentioned drawbacks.
The object is to provide a method for connecting an aluminum sheet and an aluminum ribbon-shaped lead conductor, which improves pressure-welding workability by eliminating the accumulation of fine particles.

The present invention will be described below with reference to an embodiment shown in the drawings.

As shown in FIG. 4, the upper and lower convex dies 22 and 23 each have an oval-shaped protrusion 22a with a long side and a short side, respectively.
23a.

The protrusions 22a, 23a are rounded with a small radius around the tips 32a, 33a and on the long sides of the bases 32c, 33c, as in the past, and the other side faces are machined with an appropriate draft angle. However, a round B with a large radius of curvature is formed on the short sides of the bases 32c and 33c.

This roundness B is 0.4 to 1.5 of the height H of the projections 22a and 23a, although it varies depending on the combined total thickness of the materials to be welded.
Formed with double the radius of curvature.

An aluminum sheet 1 shown in FIG.
A and a press-welded material 1 consisting of an aluminum ribbon-shaped lead conductor 1b superimposed on the end thereof are inserted and press-welded.

Then, the parts of the material 1 to be welded under pressure around the protrusions 22a, 23a are deformed, and in particular, the parts facing the short sides of the bases 32a, 33a of the protrusions 22a, 23a have little plastic flow. Although the deformation occurs with a large radius of curvature, as shown in FIG. 6, the short sides of the bases 32c and 33c of the protrusions 22a and 23a facing this portion are rounded with a small radius of curvature B. Therefore, when the material 1 is fully compressed, the surfaces of the projections 22a and 23a come into close contact with each other, and no voids are formed therebetween.

Therefore, the surface of the pressure welding material 1 and the protrusions 22a, 23a
The fine powder pieces of the press-welded material 1 generated by sliding friction with the surface do not accumulate and become small pieces, but are discharged into the incoming air.

Therefore, since there is no need for die cleaning work, the coil winding work and the pressure welding work can be performed continuously.

In addition, each convex die 22, 23 and the material 1 to be pressure welded do not engage with each other due to small pieces, and each convex die 22, 23 and the material 1 to be pressure welded do not bite.
Since it is easy to separate from the press, the pressure welding work efficiency is improved.

As described above, according to the connection method of the present invention, there is no generation of metal particles, so the pressure welding workability is improved, and it is possible to prevent dielectric breakdown accidents caused by metal particles.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the state of cold welding using the upper die and lower die, Figure 2 is a diagram showing the protrusion of the convex die, A is a plan view, the opening is a side view, and Figure 3 A is the opening. , C are cross-sectional views showing different states of the cold welding process, FIG. 4 is a cross-sectional view showing the upper and lower die used in the connection method of the present invention, and FIG. 5 is a perspective view showing the materials to be welded. FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5. 1... Material to be welded under pressure, 1a... Aluminum sheet, 1b... Aluminum ribbon-shaped lead conductor, 2
2, 23...Convex die, 22a, 23a...
...Protrusion, 32a. 33a... tip, 32b, 33b...
・Side part, 32c, 33c...Base, B...
...Roundness.

Claims (1)

[Claims] 1. A press-welded material made by overlapping an aluminum sheet and an aluminum ribbon conductor, each having an oval-shaped protrusion, is placed at the base of the short side of the protrusion at a height of 0.4 of the height of the protrusion. ~
A method of connecting an aluminum sheet and an aluminum ribbon-shaped lead conductor by cold pressure welding using upper and lower die having a radius of curvature of 1.5%.