ELECTRIC MOTOR AND ELECTRICALLY-DRIVEN OIL PUMP

摘要

PROBLEM TO BE SOLVED: To provide an electric motor capable of switching between a high-rotation low-torque type motor characteristics and high-torque low-rotation type motor characteristics, and an electrically-driven oil pump.SOLUTION: A motor rotor 4 comprises: a first rotor core 21 rotating integrally with a rotor drive shaft 9; a first magnet 22 mounted to the first rotor core 21 and including a plurality of magnetic poles; a second rotor core 23 disposed at axially one side of the first rotor core 21 and rotatable relatively to the first rotor core 21; a second magnet 24 mounted at the radially same position as the first magnet 22 of the second rotor core 23 and including magnetic poles as many as the first magnet 22; and a ratchet mechanism 25 interposed between the first rotor core 21 and the second rotor core 23 for limiting the rotation of the second rotor core 23 relative to the first rotor core 21 in a reverse direction.