A motor includes a stator, a rotor of a consequent-pole type including a rotary shaft, a bearing as a rolling bearing that supports the rotary shaft, a bearing holding part that is fixed to the stator and holds an outer ring of the bearing, and a creep prevention part. The creep prevention part is arranged between the outer ring and the bearing holding part and increases friction resistance in a circumferential direction of the outer ring between the outer ring and the bearing holding part.

A rotor includes a rotary shaft, a rotor core including a first core part and a second core part arranged to adjoin each other in a circumferential direction, and a permanent magnet provided in the first core part. A virtual magnetic pole is formed in the second core part. The first core part includes a cavity portion formed on an inner side in a radial direction of the rotor core relative to the permanent magnet. The cavity portion includes a first portion whose width in the circumferential direction increases toward the rotary shaft. A surface defining the cavity portion, being located on an innermost side of the cavity portion in the radial direction and facing outward in the radial direction is located on the inner side in the radial direction relative to an innermost portion of the second core part in the radial direction.

A rotor includes a rotary shaft, a rotor core including a first core part and a second core part arranged to adjoin each other in a circumferential direction, and a permanent magnet provided in the first core part. A virtual magnetic pole is formed in the second core part. The first core part includes a cavity portion formed on an inner side in a radial direction of the rotor core relative to the permanent magnet. The cavity portion includes a first portion whose width in the circumferential direction increases toward the rotary shaft. A surface defining the cavity portion, being located on an innermost side of the cavity portion in the radial direction and facing outward in the radial direction is located on the inner side in the radial direction relative to an innermost portion of the second core part in the radial direction.

A motor includes a rotor including a rotor core fixed to a rotary shaft of a compressor, and permanent magnets fixed to the rotor core, and a stator including a stator core surrounding the rotor core from outside in a radial direction about a central axis of the rotary shaft. The rotor core has a first core and a second core in a direction of the central axis. The first core has a hole portion at a center thereof in the radial direction, and has magnet insertion holes located on an outer side of the hole portion in the radial direction. The permanent magnet is inserted in the magnet insertion hole. The permanent magnet constitutes a magnet magnetic pole, and a part of the first core constitutes a pseudo magnetic pole. The second core has a shaft hole at a center thereof in the radial direction. The rotary shaft is fixed to the shaft hole. An inner circumference of the hole portion of the first core is distanced from the rotary shaft in the radial direction. The second core is located on an outer side of the stator core in the direction of the central axis.

A polyphase electric motor includes a stator having at least three coils and made up of 12.K radially extending teeth, and a rotor having 5.K pairs of magnetic poles, K being equal to 1 or 2. The rotor includes a core made of a ferromagnetic material and has an alternation of 5K magnetized poles, and 5K non-magnetized salient poles. The stator has teeth with rectangular or trapezoidal cross-sections converging towards the center of the motor.

A permanent magnet motor, including: a stator assembly and a rotor assembly. The stator assembly includes: a stator core and a coil winding. The stator core includes: a yoke portion, a plurality of tooth portions, and a plurality of winding slots. The rotor assembly includes: a rotor core, a plurality of permanent magnets, and a rotor sheath. The tooth portions are extended out of the yoke portion. Each winding slot is formed between adjacent tooth portions. The permanent magnets are disposed at intervals on a surface of the rotor core and magnetic poles of two facing sides of adjacent permanent magnets are the same. The rotor sheath is disposed outside the rotor assembly and is divided into at least two segments axially. A magnetic conductivity of a first segment of the rotor sheath is different from a magnetic conductivity of a second segment of the rotor sheath.

A rotor has a projection part projected from an inner wall of a central hole part toward a central axis and a rib part defined between opening parts adjacent with each other in a circumferential direction. A first imaginary straight line is defined to extend from the central axis outward in a radial direction through a center of the projection part. The projection part is formed so that the first imaginary straight line passes the opening part. A second imaginary straight line is defined to extend from the central axis outward in the radial direction through a center of the rib part. The rib part is formed so that the second imaginary straight line passes a center of a pole part or an intermediate position between pole parts adjacent with each other in the circumferential direction.

A rotor includes first and second rotor cores, a field magnet, and an annular magnet. The first and second rotor cores each include a core base and core magnetic poles. The core magnetic poles are provided on an outer peripheral portion of the core base at equal intervals. The core bases are faced with each other. The core magnetic poles are alternately arranged in a peripheral direction. The annular magnet is a resin molding product including a magnetic pole magnet portion and an inter-pole magnet portion. The annular magnet has a non-contact portion not in contact with the first and second rotor cores. A gate mark portion in injection molding of the annular magnet is arranged in the non-contact portion.

A rotor includes a rotor core, a permanent magnet, a first part, a second part, and a third part. The third part is formed integrally with the first part and the second part. The rotor core is longer than the permanent magnet in an axial direction.

A rotor includes a rotor core, a permanent magnet, a first part, a second part, and a third part. The third part is formed integrally with the first part and the second part. The rotor core is longer than the permanent magnet in an axial direction.