Method of producing an armature segment of an electrical machine

An armature segment of an electrical machine includes a coil and a core section. A method of producing such a segment comprises the steps of tightly winding the coil, providing a compaction die having a cavity for shaping the tightly wound coil, introducing the tightly wound coil into the compaction die and compacting the coil therein so as to reduce the volume occupied by the coil, providing a compression-moulding die having a moulding cavity, positioning the compacted coil in the moulding cavity of the compression die, filling the moulding cavity with insulated ferromagnetic particles, and compressing the insulated ferromagnetic particles in the moulding cavity so as to form the armature segment as a single-piece unit including the core section and the compacted coil.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pre-compacted coil used in the method according to the present invention;

FIG. 2 is a cross-sectional view of a die used for pre-compaction of the coil before compression thereof with a ferromagnetic metal powder;

FIG. 3 is a cross-sectional view of a part of the coil of FIG. 1 resulting from the compacting using the die of FIG. 2;

FIG. 4 is a cross-sectional view of a compression die showing the compacted coil positioned therein;

FIG. 5 is a cross-sectional view, taken in a plane normal to the planes of FIGS. 2 and 4, of a co-compressed coil and core unit forming an armature segment according to the invention.

1. A method of producing an armature segment of an electrical machine, which armature segment includes a coil and a core section, the method comprising the steps of

2. A method as claimed in claim 1, wherein the tightly wound coil introduced into the compaction die is compacted so as to deform a cross-sectional area of individual wires of the coil towards a hexagonal shape.

3. A method as claimed in claim 1, wherein the compaction die partly is used as the compressing-molding die.

4. A method as claimed in claim 1, wherein the coil is positioned in the molding cavity of the compressing-molding die so as to form a surface layer of the armature segment.

5. A method as claimed in claim 1, wherein the coil is positioned in the molding cavity of the compression-molding die separated from surfaces thereof.

6. A method as claimed in claim 1, wherein the coil is preformed on a bobbin.

7. A method as claimed in claim 1, wherein the compressing is performed at an elevated temperature.

8. A method as claimed in claim 2, wherein the compaction die partly is used as the compressing-molding die.

9. A method as claimed in claim 2, wherein the coil is positioned in the molding cavity of the compressing-molding die so as to form a surface layer of the armature segment.

10. A method as claimed in claim 3, wherein the coil is positioned in the molding cavity of the compressing-molding die so as to form a surface layer of the armature segment.

11. A method as claimed in claim 8, wherein the coil is positioned in the molding cavity of the compressing-molding die so as to form a surface layer of the armature segment.

12. A method as claimed in claim 2, wherein the coil is preformed on a bobbin.

13. A method as claimed in claim 3, wherein the coil is preformed on a bobbin.

14. A method as claimed in claim 4, wherein the coil is preformed on a bobbin.

15. A method as claimed in claim 5, wherein the coil is preformed on a bobbin.

16. A method as claimed in claim 2, wherein the compressing is performed at an elevated temperature.

17. A method as claimed in claim 3, wherein the compressing is performed at an elevated temperature.

18. A method as claimed in claim 4, wherein the compressing is performed at an elevated temperature.

19. A method as claimed in claim 5, wherein the compressing is performed at an elevated temperature.

20. A method as claimed in claim 6, wherein the compressing is performed at an elevated temperature.