Patent ID: 7030529
Filing Date: 2006-04-18
Classification: H02K

Abstract:
1. In a permanent magnet-excited electric motor ( 10 ) having a rotating rotor ( 11 ) including a rotor shaft ( 12 ) and permanent magnets ( 13 ) disposed in a ring around its circumference, which magnets cooperate with coils ( 15 ) of a stator ( 16 ) encompassing the rotor, the improvement wherein the permanent magnets ( 13 , 13 ′) are individual magnets disposed next to one another and distributed uniformly over the circumference of the rotor ( 11 ) and resting on an annular support ( 21 ), and at least one respective annular frame ( 22 , 22 a , 23 , 24 , 24 a ) comprised of magnetically inactive material, clamping the magnets ( 13 , 13 ′) in place at their axial ends ( 13 a , 13 b , 13 a ′, 13 b ′), the support ( 21 ) and/or the at least one respective frame ( 22 , 22 a , 23 , 24 , 24 a ) being attached to the rotor shaft ( 12 ), wherein the end surfaces of the at least one respective frame ( 22 , 22 a , 23 , 24 , 24 a ) are provided with respective recesses ( 26 ), each of which receives an axial end ( 13 a , 13 a′ , 13 b , 13 b ′) of one of the permanent magnets ( 13 , 13 ′) and wherein the axial ends ( 13 a , 13 a ′, 13 b , 13 b ′) of the permanent magnets ( 13 , 13 ′) are fixed in the recesses ( 26 ) in the radial, axial, and circumferential directions, wherein the opposite sides of the ends ( 13 a , 13 b ) of the permanent magnets ( 13 ) are provided with shaped bevels ( 27 ), which cause the ends ( 13 a , 13 b ) to taper toward their end surfaces and are received in a positively engaging manner by corresponding negative shaped bevels ( 28 ) in the recesses ( 26 ) of the at least one frame ( 22 , 23 , 24 ), and wherein the end surface ( 13 c ) of the ends ( 13 a , 13 b ) of the permanent magnets ( 13 ) are provided with additional shaped bevels ( 29 ), which reduce the axial length of the permanent magnets ( 13 ) along the surfaces of the permanent magnets most distant from the circumferential surface of the rotor and are received in positively engaging manner by corresponding negative shaped bevels ( 30 ) in the recesses ( 26 ).