Abstract: A rotor core has first and second magnet insertion holes along an outer circumference, and first and second slits along an inner circumference. The first and second slits have first and second facing portions facing each other. The first facing portion has a first inner end and a first outer end. The second facing portion has a second inner end and a second outer end. An inter-slit portion is provided between the first and second facing portions and is defined by a first straight line connecting the first and second inner ends and a second straight line connecting the first and second outer ends. In a radial direction of the rotor core, a minimum distance D1 from the inner circumference to the slits, a minimum width W1 of the slits, and a length W2 of the inter-slit portion satisfy at least one of D1<W1 and D1<W2.

Abstract: An electric motor includes a stator and a rotor including a permanent magnet and an electromagnetic steel sheet. The electromagnetic steel sheet includes a magnet insertion hole, a first outer peripheral surface including an inter-pole part of the rotor, a second outer peripheral surface including a magnetic pole center part of the rotor, a first slit elongated in a circumferential direction of the rotor, and a first portion formed between the first slit and the magnet insertion hole. A distance from the first outer peripheral surface to the stator is larger than a distance from the second outer peripheral surface to the stator. The electric motor satisfies ?a<?b, where ?a is a first angle formed by a first line and a second line and ?b is a second angle formed by a third line and the second line.

Abstract: A rotor includes a first permanent magnet, a second permanent magnet, and an electromagnetic steel sheet. The electromagnetic steel sheet includes a magnet insertion hole, a projection, a first end part, a second end part (211b), a third end part, and a fourth end part. The rotor satisfies an expression of t?2×w×sin(R/2)?2×t, where t is a thickness of the electromagnetic steel sheet, R is an angle formed by the third end part and the fourth end part, and w is a distance from an intersection point of a straight line including the first end part and a straight line including the third end part to an intersection point of a straight line including the third end part and a straight line including the fourth end part.

Abstract: A magnetizing method includes the steps of preparing a rotor comprising a rotor core having a magnet insertion hole and a permanent magnet provided in the magnet insertion hole, placing the rotor so as to face a tooth around which a winding is wound, rotating the rotor in a first rotating direction by a first angle ?1 from a rotational position where a center of the magnet insertion hole in a circumferential direction of the rotor core faces a middle portion between both ends of the winding in the circumferential direction and supplying electric current to the winding, and rotating the rotor in a second rotating direction opposite to the first rotating direction by a second angle ?2 from the rotational position direction and supplying electric current to the winding. The second angle ?2 is smaller than the first angle ?1.

Abstract: A rotor includes a rotor core having a magnet insertion hole and a permanent magnet provided in the magnet insertion hole. The rotor core has a slit on an outer side of the magnet insertion hole in a radial direction of the rotor core. The permanent magnet is magnetized by placing the rotor so as to face a tooth around which a winding is wound, rotating the rotor in a first rotating direction from a rotational position where a center of the magnet insertion hole in a circumferential direction of the rotor core faces a middle portion between both ends of the winding in the circumferential direction and supplying electric current to the winding, and rotating the rotor in a second rotating direction opposite to the first rotating direction from the rotational position and supplying electric current to the winding.

Abstract: A rotor includes an electromagnetic steel sheet and a permanent magnet. The electromagnetic steel sheet includes a magnet insertion hole, a slit, a first end part, a second end part, a third end part, a fourth end part, and a fifth end part. Expressions of L1>L2 and L3?L2 are satisfied, where L1 is a distance from the first end part to the magnet insertion hole, L2 is a distance from a first boundary between the first end part and the second end part to the magnet insertion hole, and L3 is a distance from a second boundary between the second end part and the third end part to the magnet insertion hole.

Abstract: A rotor core has first and second magnet insertion holes along an outer circumference, and first and second slits along an inner circumference. The first and second slits have first and second facing portions facing each other. The first facing portion has a first inner end and a first outer end. The second facing portion has a second inner end and a second outer end. An inter-slit portion is provided between the first and second facing portions and is defined by a first straight line connecting the first and second inner ends and a second straight line connecting the first and second outer ends. In a radial direction of the rotor core, a minimum distance D1 from the inner circumference to the slits, a minimum width W1 of the slits, and a length W2 of the inter-slit portion satisfy at least one of D1<W1 and D1<W2.

Abstract: An electric motor includes a stator and a rotor including a permanent magnet and an electromagnetic steel sheet. The electromagnetic steel sheet includes a magnet insertion hole, a first outer peripheral surface including an inter-pole part of the rotor, a second outer peripheral surface including a magnetic pole center part of the rotor, a first slit elongated in a circumferential direction of the rotor, and a first portion formed between the first slit and the magnet insertion hole. A distance from the first outer peripheral surface to the stator is larger than a distance from the second outer peripheral surface to the stator. The electric motor satisfies ?a<?b, where ?a is a first angle formed by a first line and a second line and ?b is a second angle formed by a third line and the second line.

Abstract: A stator of an electric motor (40) has windings (44) and a stator core (43) in which eighteen teeth (71), around which the windings (44) are wound, are formed circumferentially. A rotor of the electric motor (40) has magnets (72) and a rotor core (46) in which six insertion holes (73), into which the magnets (72) are inserted, are formed circumferentially. The magnets (72) are rare-earth magnets of a grain boundary diffusion type having a residual magnetic flux density Br of from 1.36 to 1.42 T. The total area of magnet-parallel cross-sections (84) of the teeth (71) is from 0.56 times to 0.93 times the total area of tooth-facing surfaces (83) of the magnets (72).

Abstract: A rotor includes an electromagnetic steel sheet and a permanent magnet. The electromagnetic steel sheet includes a magnet insertion hole, a slit, a first end part, a second end part, a third end part, a fourth end part, and a fifth end part. Expressions of L1>L2 and L3?L2 are satisfied, where L1 is a distance from the first end part to the magnet insertion hole, L2 is a distance from a first boundary between the first end part and the second end part to the magnet insertion hole, and L3 is a distance from a second boundary between the second end part and the third end part to the magnet insertion hole.

Abstract: A rotor includes a first permanent magnet, a second permanent magnet, and an electromagnetic steel sheet. The electromagnetic steel sheet includes a magnet insertion hole, a projection, a first end part, a second end part (211b), a third end part, and a fourth end part. The rotor satisfies an expression of t?2×w×sin(R/2)?2×t, where t is a thickness of the electromagnetic steel sheet, R is an angle formed by the third end part and the fourth end part, and w is a distance from an intersection point of a straight line including the first end part and a straight line including the third end part to an intersection point of a straight line including the third end part and a straight line including the fourth end part.

Abstract: A rotor includes a rotor core having a magnet insertion hole and a permanent magnet provided in the magnet insertion hole. The rotor core has a slit on an outer side of the magnet insertion hole in a radial direction of the rotor core. The permanent magnet is magnetized by placing the rotor so as to face a tooth around which a winding is wound, rotating the rotor in a first rotating direction from a rotational position where a center of the magnet insertion hole in a circumferential direction of the rotor core faces a middle portion between both ends of the winding in the circumferential direction and supplying electric current to the winding, and rotating the rotor in a second rotating direction opposite to the first rotating direction from the rotational position and supplying electric current to the winding.

Abstract: A magnetizing method includes the steps of preparing a rotor comprising a rotor core having a magnet insertion hole and a permanent magnet provided in the magnet insertion hole, placing the rotor so as to face a tooth around which a winding is wound, rotating the rotor in a first rotating direction by a first angle ?1 from a rotational position where a center of the magnet insertion hole in a circumferential direction of the rotor core faces a middle portion between both ends of the winding in the circumferential direction and supplying electric current to the winding, and rotating the rotor in a second rotating direction opposite to the first rotating direction by a second angle ?2 from the rotational position direction and supplying electric current to the winding. The second angle ?2 is smaller than the first angle ?1.

Abstract: A stator of an electric motor (40) has windings (44) and a stator core (43) in which eighteen teeth (71), around which the windings (44) are wound, are formed circumferentially. A rotor of the electric motor (40) has magnets (72) and a rotor core (46) in which six insertion holes (73), into which the magnets (72) are inserted, are formed circumferentially. The magnets (72) are rare-earth magnets of a grain boundary diffusion type having a residual magnetic flux density Br of from 1.36 to 1.42 T. The total area of magnet-parallel cross-sections (84) of the teeth (71) is from 0.56 times to 0.93 times the total area of tooth-facing surfaces (83) of the magnets (72).

Abstract: An electric motor including: a stator having a cylindrical shape and including a stator core and a stator winding wound around the stator core; and a rotor rotatably disposed inside the stator, the stator winding includes a plurality of windings connected in series in each phase, the plurality of windings in each phase are constituted by both copper wire and aluminum wire, and a ratio between the aluminum wire and the copper wire is uniform among phases.

Abstract: A rotor of a permanent magnet embedded motor according to this invention includes: a rotor iron core formed by stacking a predetermined number of electromagnetic steel plates perforated in a predetermined shape; a plurality of permanent magnet insertion holes formed along an outer circumferential section of the rotor iron core; permanent magnet end gaps provided at both ends of the permanent magnet insertion hole; a permanent magnet inserted in the permanent magnet insertion hole; and a plurality of slits formed in an iron core section on the outer side of the permanent magnet insertion hole. The width in the radial direction of a slit thin section of each of the slits between the slit and the rotor iron core outer circumference gradually increases from an inter-electrode side toward a magnetic pole center and changes in a sine wave shape having a peak in the magnetic pole center.

Abstract: An induction motor includes a stator having a winding to be inserted to a plurality of stator slots formed along an inner circumferential edge of a stator iron core; and a rotor placed inside of the stator via a gap, the rotor includes a plurality of double squirrel-cage rotor slots formed along an outer circumferential edge of the rotor iron core and filled with conductive material and at least three air hole parts provided around a rotating shaft hole of the rotor iron core to which the rotating shaft is fitted and having an opening which is open to the rotating shaft hole; and an inner diameter part of the end ring which short circuits both edges of the conductive material filled to the double squirrel-cage rotor slot is placed to be adjacent to the air hole part in at least the end ring of one side.

Abstract: A rotor of a permanent magnet embedded motor according to this invention includes: a rotor iron core formed by stacking a predetermined number of electromagnetic steel plates perforated in a predetermined shape; a plurality of permanent magnet insertion holes formed along an outer circumferential section of the rotor iron core; permanent magnet end gaps provided at both ends of the permanent magnet insertion hole; a permanent magnet inserted in the permanent magnet insertion hole; and a plurality of slits formed in an iron core section on the outer side of the permanent magnet insertion hole. The width in the radial direction of a slit thin section of each of the slits between the slit and the rotor iron core outer circumference gradually increases from an inter-electrode side toward a magnetic pole center and changes in a sine wave shape having a peak in the magnetic pole center.

Abstract: A motor for a compressor comprises: a stator including a plurality of slots each having a slot opening, teeth formed between neighboring slots; and a rotor arranged at an inner side of the stator, a number of permanent magnet holes, the number of which is same as a number of magnetic poles, and permanent magnets. The rotor includes at least a first pair of slits, provided at an outer peripheral core part of the permanent magnet inserting hole, extending orthogonally to the inserting hole, arranged symmetrically with respect to a magnetic pole center, and a distance between the first pair of slits is smaller than a width of the teeth; and a second pair of slits, arranged at an outer inter-pole side of the first pair of slits, provided at a position where the tooth and the magnetic pole center of the rotor match, and facing the slot openings.

Abstract: It is an object to obtain a highly efficient induction motor which does not degrade the fitting strength of shrink-fit and of which the starting torque is high, and further to obtain a highly reliable hermetic compressor which suppresses the oil amount flowing out of the hermetic compressor.