Patent ID: 6995489
Filing Date: 2006-02-07
Classification: H02K

Abstract:
1. An electric machine ( 2 ) comprising a rotor ( 4 ) and a stator ( 6 ) arranged coaxially therewith, said rotor ( 4 ) comprising permanent magnets ( 14 ) and a magnetic yoke ( 12 ) and a bandage ( 16 ) holding together the permanent magnets ( 14 ) and the magnetic yoke ( 12 ) in use against centrifugal forces, the bandage ( 16 ) being arranged on the rotor ( 4 ) with a bias which is selected that in use the bandage ( 16 ), under the effect of centrifugal forces, expands in minimum manner only, so that the bandage maintains the structural integrity of the rotor, wherein the bandage and the rotor are formed from materials such that the coefficients of thermal expansion of the rotor and the bandage in a circumferential direction differ from each other at most by 50%, wherein the bandage ( 16 ) comprises a unidirectional fiber material which is located in a plastic matrix, which fiber material is an electrically nonconductive fiber material having a coefficient of thermal expansion which is at most by a factor of 2 larger or smaller than that of the rotor ( 4 ); and wherein the ceramic fiber material has a modulus of elasticity of higher than 300 GPa.