US 8,946,967 B2 · Electric rotating machine

Abstract

A tooth portion of a stator is divided into first and second tooth portions and in a relatively movable manner between a first position in which a magnetic resistance between the tooth portions is small and a second position in which the magnetic resistance is relatively larger than in the first position. When the second tooth portion is in the first position, the following equation is satisfied: (total magnetic resistance of main magnetic circuit C1)<(total magnetic resistance of magnetic short-circuit C2)≦(total magnetic resistance of magnetic circuit between permanent magnets C3). When the second tooth portion is in the second position, it is satisfied: (total magnetic resistance of the magnetic short-circuit C2)<(total magnetic resistance of the main magnetic circuit C1), and (total magnetic resistance of the magnetic short-circuit C2)≦(total magnetic resistance of the magnetic circuit between permanent magnetics C3).

An electric rotating machine, comprising:

a rotor having a plurality of permanent magnets, including first and second permanent magnets adjacent each other, embedded in a columnar rotor main body and configured to rotate about a rotation axis;
and
a cylindrical stator arranged outward of the rotor in a radial direction of the rotor so as to face an outer peripheral surface of the rotor main body via a gap, the stator including
a plurality of tooth portions arranged at intervals in a circumferential direction of the stator, a first and a second of the tooth portions being adjacent each other, each of the plurality of tooth portions including
a body portion that has a pair of sides arranged opposite each other in the circumferential direction, the pair of sides having rotor side end portions, and
a pair of side protruded portions protruding in the circumferential direction from the rotor side end portions of the pair of sides,
a stator yoke portion which forms a stator magnetic path together with the tooth portions,
windings arranged around the tooth portions, and
a magnetic resistance changing mechanism configured to change a magnetic resistance of the stator magnetic path by mechanically changing the stator magnetic path,
wherein the magnetic resistance changing mechanism is configured to mechanically change the stator magnetic path between a first state and a second state in which the magnetic resistance of the stator magnetic path is larger than that of the stator magnetic path in the first state,
wherein a main magnetic circuit C1 is defined as a magnetic circuit having a main magnetic path that extends from one of the magnetic poles of the first permanent magnet, and reaches the other magnetic pole of the first permanent magnet via a stator yoke portion side of the first tooth portion, the second tooth portion, and the second permanent magnet, wherein the stator yoke portion side of the first tooth portion is disposed closer to the stator yoke portion than any other side of the first tooth portion,
wherein a magnetic short-circuit C2 is defined as a magnetic circuit having a main magnetic path that extends from the one magnetic pole of the first permanent magnet and reaches the other magnetic pole of the first permanent magnet via the second permanent magnet, one of the side protruded portions of the first tooth portion and one of the side protruded portions of the second tooth portion, without passing through the stator yoke portion side of the first tooth portion and a stator yoke portion side of the second tooth portion,
wherein a magnetic circuit between permanent magnets C3 is defined as a magnetic circuit having a main magnetic path that extends from the one magnetic pole of the first permanent magnet and reaches the other magnetic pole of the first permanent magnet via the one side protruded portion of the first tooth portion, and an intermediate region between the first and second permanent magnets, without passing through the stator yoke portion side of the first tooth portion and the second tooth portion,
wherein in the first state, the following relational expression is satisfied:
a total magnetic resistance of the main magnetic circuit C1<a total magnetic resistance of the magnetic short-circuit C2≦a total magnetic resistance of the magnetic circuit between permanent magnets C3,
wherein in the second state, both the following relational expressions are satisfied:
the total magnetic resistance of the magnetic short-circuit C2<the total magnetic resistance of the main magnetic circuit C1, and
the total magnetic resistance of the magnetic short-circuit C2≦the total magnetic resistance of the magnetic circuit between permanent magnets C3.

15 more elements

Electric rotating machine

Life of this patent

Electric rotating machine

Life of this patent

Abstract

Claims19