Rotors for electrical machines

A method of manufacturing a rotor for an electric machine the method comprising:

• providing a rotor body having an external, axially extending magnet receiving surface, and a flange mounting portion at least one axial end of the external surface and having a smaller external dimension (D1) than an external dimension (D2) of the magnet receiving surface to form a shoulder therebetween;
• mounting a magnet retaining flange over the flange mounting portion of the rotor body and against the shoulder;
• and
• retaining the flange against the shoulder by deforming a radially outer peripheral portion of the flange mounting portion of the rotor body adjacent the retaining flange such that the radially outer peripheral portion of the flange mounting portion is a lip, wherein the lip extends over a radially inner portion of the retaining flange;
• wherein the flange mounting portion comprises a plurality of the lips, the plurality of lips being circumferentially spaced lips, the method further comprising:
• deforming a plurality of circumferentially spaced regions of the flange mounting portion of the rotor body to form a plurality of circumferentially spaced lips;
• wherein the deforming comprises pressing a deforming element into a radially outer peripheral region of an end face of the flange mounting portion of the rotor body so as to form an indentation therein and locally to deform the peripheral region radially outwardly to form the lip.