Electrical machines, especially engines excited by permanent magnets

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, 22a, 23, 24, 24a) comprised of magnetically inactive material, clamping the magnets (13,13′) in place at their axial ends (13a, 13b, 13a′, 13b′), the support (21) and/or the at least one respective frame (22, 22a, 23, 24, 24a) being attached to the rotor shaft (12), wherein the end surfaces of the at least one respective frame (22, 22a, 23, 24, 24a) are provided with respective recesses (26), each of which receives an axial end (13a, 13a′, 13b, 13b′) of one of the permanent magnets (13, 13′) and wherein the axial ends (13a, 13a′, 13b, 13b′) 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 (13a, 13b) of the permanent magnets (13) are provided with shaped bevels (27), which cause the ends (13a, 13b) 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 (13c) of the ends (13a, 13b) 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).