Synchronous reluctance type rotary electric machine
A synchronous reluctance type rotary electric machine of an embodiment includes, a rotor core, a plurality of conductor bars, short-circuit rings, a stator core, and multiphase armature windings. The rotor core includes multi-layered hollow parts having a convex shape toward a side radially inward formed for each pole in cross section, and a bridge formed between each of the hollow parts and an outer circumferential surface thereof. The plurality of conductor bars are disposed in the respective hollow parts. The short-circuit rings connect the plurality of conductor bars together. Then, in all of the hollow parts of a second layer and subsequent layers other than the hollow part of a first layer which is at a position farthest from the rotation axis of the rotor core, the conductor bars are disposed at both end portions thereof close to the bridge at a predetermined distance from the bridge.
1. A synchronous reluctance type rotary electric machine comprising:
a rotor core provided to be rotatable around a rotation axis, and including multi-layered hollow parts having a convex shape toward a side radially inward formed for each pole in cross section, and a bridge formed between each of the hollow parts and an outer circumferential surface thereof along the outer peripheral surface;
a plurality of conductor bars disposed in the respective hollow parts and extending in an axial direction and over approximately entire length of the rotor core;
short-circuit rings provided at both ends of each of the plurality of conductor bars and connecting the plurality of conductor bars together;
a stator core disposed on an outer circumference of the rotor core to be spaced apart from the rotor core and including a plurality of teeth disposed at intervals in a circumferential direction; and
multipole multiphase armature windings respectively wound around the plurality of teeth, wherein
in all of the hollow parts of a second layer and subsequent layers other than the hollow part of a first layer which is at a position farthest from the rotation axis of the rotor core, the conductor bars are disposed at both end portions thereof close to the bridge at a predetermined distance from the bridge.
2. The synchronous reluctance type rotary electric machine according to claim 1 , wherein
when a predetermined distance between the bridge and the conductor bar is W, a gap between an outer circumferential surface of the rotor core and the stator core is G, a width in a direction along the outer circumferential surface at the both end portions of the hollow part is L, a saturation magnetic flux density of the rotor core is Bs, a thickness of the bridge is Wb, a current density of the conductor bar is J, a cross-sectional area of the conductor bar in a direction perpendicular to the rotation axis is S, and a magnetic permeability of the hollow part is μ, the predetermined distance W is set to satisfy
G<W ≤( L×Bs×Wb )/(μ× J×S ).