| 摘要 |
An electric motor has a rotor (36) and a stator (28) having a lamination stack formed with slots (126). The slots have a predetermined slot pitch (tauS), and a multi-phase stator winding is arranged in them. The rotor (36) has salient poles having pole shoes (136) and a magnetic return path (130). Between the return path (130) and each pole shoe (136), a recess (138, 140) is formed for receiving a permanent magnet (38). On each side of such a permanent magnet (38), a region (146a, 146b) of poor magnetic conductivity is arranged, in order to make the flux distribution in the air gap more sinusoidal. Measuring in a circumferential direction, the width (beta) of a pole shoe (136) decreases with increasing distance from an interface (138) between said return path and said permanent magnet (38), and, at a place of lowest width, the pole shoe has an angular extent (betaC)which has, with respect to the slot pitch (tauS) between said stator slots (126), the following relationship: betaC=n*tauS*(1-0.02) . . . n*tauS*(1-0.2), where n=1, 2, 3 . . . and betaC and tauS are measured in mechanical degrees.
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