Synchronous reluctance type rotary electric machine

1. A synchronous reluctance type rotary electric machine comprising:

a rotor core including a plurality of poles, 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, wherein,

when a boundary between two adjacent poles is a pole boundary, a groove is formed on at least one of both sides sandwiching the pole boundary at positions other than on the pole boundary on the outer circumferential surface of the rotor core, and

when a center in a circumferential direction of one pole is a pole center,

a second groove is formed on an outer circumferential surface of the bridge positioned next to the bridge closest to the pole center, and

a groove depth of the second groove is set to gradually increase toward the pole center.

2. The synchronous reluctance type rotary electric machine according to claim 1 , wherein the groove is formed over the entire rotor core in a direction of a rotation axis.

3. The synchronous reluctance type rotary electric machine according to claim 1 , wherein the groove is formed within a range of the bridge at a position closest to the pole boundary.

4. The synchronous reluctance type rotary electric machine according to claim 1 , wherein a groove depth of the groove is set to gradually increase toward the pole boundary.