Filament winding

Carbon fibre sleeves offer high strength and stiffness at low weight. As they also leave magnetic fields undisturbed, they are ideally suited as reinforcement against the high centrifugal forces acting on the fast-rotating rotors of electric motors and generators.

Winding the rotor directly allows high pre-tension to be achieved in the carbon fibre sleeve. Compared with a press-fitted composite sleeve, the process steps of machining the magnets and pressing on the sleeve are eliminated. No special mandrel is needed to produce a sleeve, which makes direct winding economical for one-offs and small series as well as for large rotors. Because the carbon fibre is laid directly onto the magnet under tension, the rotor sleeve is stressed evenly across its entire wall thickness. Unlike round sleeves, directly wound rotors allow the areas between the magnets to be spanned with straight fibre.