Rotor for a high speed permanent magnet motor

A rotor for a high speed permanent magnet motor comprising:

• a central spindle,
• a plurality of magnet discs stacked on said spindle,
• a clamping device provided on said spindle for exerting an axial clamping force on said magnet discs, thereby forming an axially pre-tensioned disc packet, and
• a reinforcement disc of a non-magnetic high-strength material provided at least one of (i) between at least every second magnetic disc, and (ii) between at least one of said magnetic discs and said clamping device,
• wherein the reinforcement discs have substantially a same outer dimension as the magnet discs, and
• wherein each reinforcement disc is clamped by said axial clamping force between said at least every second magnet disc or between said at least one magnet disc and said clamping device, thereby accomplishing a frictional engagement between said reinforcement discs and said magnet discs for transferring centrifugal forces from said magnet discs to said reinforcement discs, and thereby relieving said magnet discs of tensile stress.