Method and device for deforming U-shaped electric conductors

#This is a National Stage Application, filed under 35 U.S.C. 371, of International Patent Application No. PCT/EP2018/062243, filed on May 11, 2018, which claims priority to German patent application No. 102017004538.0 filed on May 11, 2017, contents of both of which are incorporated herein by reference in their entireties.

#The invention relates to a method and device for deforming a U-shaped electric conductor which is rectangular in cross section into a hairpin, which is used for the production of a bar winding of an electric machine, wherein before the deforming process the electric conductor has two mutually parallel limbs which are integrally connected to each other by means of a connection limb, and in which the three limbs are disposed in an imaginary, flat plane.

#In the context of the invention, the term “electric machine” is understood to mean only electric motors and electric generators which convert electrical energy into mechanical energy or mechanical energy into electrical energy.

#The invention will be explained below with reference to several embodiments shown in the attached drawing. Shown in the drawing are:

#FIG. 1 a schematic representation of a known bending device for bending a U-shaped electric conductor from a wire,

#FIG. 2 a schematic representation of such an electric conductor with an imaginary flat plane between the limbs of the conductor,

#Accordingly, FIG. 1 shows a schematic representation of a known bending device 1* for bending a U-shaped electric conductor 6 from a wire 2. For this purpose, the wire 2 is fed to a first roller 3 and bent around the surface of the first roller 3 in an arc-shape by means of a second roller 4. As soon as the two parallel limbs 7, 8 have a desired length, the wire 2 is severed by means of a cutting device 5 and the U-shaped electric conductor 6 is removed from the bending device 1* for further deforming.

#In deviation from this prior art, the cutting of the wire 2 according to the invention preferably takes place only when the deforming process to be described below is completed. This approach has the advantage that the U-shaped bent wire 2 must be handled as a single part only after its final deforming.

#As FIG. 2 shows, the electric conductor 6 has a largely semicircular connection limb 9, which connects the two parallel limbs 7, 8 in one piece. The three limbs 7, 8, 9 of the electric conductor 6 are aligned with each other such that they span an imaginary, flat plane 10 between them. Such an electric conductor 6 serves as a precursor for producing a hairpin 19 shown in FIG. 4, whose limbs 7, 8, 9 no longer lie in the same imaginary plane 10. For this purpose, the electric conductor 6 must be deformed, wherein the deformation is carried out substantially in the area of the connection limb 9, so that the two other limbs 7, 8 still have a straight geometry, but are no longer disposed in the same, imaginary plane.