An electric sander motor includes a motor main body (100), a power axial shaft (210) and a sleeve (220). The motor main body (100) includes a rotor (110) and a stator (120) surrounding the rotor (110). The power axial shaft (210) includes an axial hole (211) extending along a central axis of the power axial shaft (210). The sleeve (220) includes one open end and another closed end extended outward to form an eccentric axial shaft (221) penetrating through the axial hole (211). A central axis of the eccentric axial shaft (211) is parallel with a central axis of the sleeve (220) and spaced apart therefrom. The power axial shaft (210) penetrates through the rotor (110), and the sleeve (220) is outside the motor main body (100). The assembly is facilitated by assembling the power axial shaft (210) and the sleeve (220) onto the motor main body (100) sequentially.

A permanent magnet for a permanent magnet machine, a permanent magnet machine, a method for manufacturing a permanent magnet for a permanent magnet machine, and a method for manufacturing a permanent magnet machine is provided. The permanent magnet includes a base body, and at least one first fixing protrusion for fixing the base body to a rotor of the permanent magnet machine, wherein the first fixing protrusion extends from a first side of the base body, and wherein the base body and the at least one first fixing protrusion are formed integrally as one-piece.

A permanent magnet for a permanent magnet machine, a permanent magnet machine, a method for manufacturing a permanent magnet for a permanent magnet machine, and a method for manufacturing a permanent magnet machine is provided. The permanent magnet includes a base body, and at least one first fixing protrusion for fixing the base body to a rotor of the permanent magnet machine, wherein the first fixing protrusion extends from a first side of the base body, and wherein the base body and the at least one first fixing protrusion are formed integrally as one-piece.

An electric work machine includes: a brushless motor including: a rotor having permanent magnets fixed to a rotor core; a stator core; one or more insulators fixed to the stator core; and a stator including coils mounted on the insulator(s); magnetic sensors, which detect the position of the rotor in a rotational direction by detecting the magnetic flux of the permanent magnets; a controller, which controls energization of the coils based in part on detection signals of the magnetic sensors; and an output part driven by the rotor. The permanent magnets are each a neodymium, sintered, plate magnet. The pole count (N) is the number of permanent magnets. The stator diameter (x) is the diameter of a surface of the stator core that faces the rotor in millimeters. The following condition is satisfied: 0.16x+2.5<N<0.23x+3.6.

An electric work machine includes: a brushless motor including: a rotor having permanent magnets fixed to a rotor core; a stator core; one or more insulators fixed to the stator core; and a stator including coils mounted on the insulator(s); magnetic sensors, which detect the position of the rotor in a rotational direction by detecting the magnetic flux of the permanent magnets; a controller, which controls energization of the coils based in part on detection signals of the magnetic sensors; and an output part driven by the rotor. The permanent magnets are each a neodymium, sintered, plate magnet. The pole count (N) is the number of permanent magnets. The stator diameter (x) is the diameter of a surface of the stator core that faces the rotor in millimeters. The following condition is satisfied: 0.16x+2.5<N<0.23x+3.6.

A rotor for a rotary electric machine includes a rotor core in which a plurality of magnetic pole portions is provided. Each of the magnetic pole portions includes: a magnet insertion hole into which a permanent magnet is inserted. A d-axis-side space portion is provided inside the magnet insertion hole between the d-axis-side end portion of the permanent magnet and the d-axis-side end portion of the magnet insertion hole, and a q-axis-side space portion penetrating in the axial direction is provided inside the magnet insertion hole between the q-axis-side end portion of the permanent magnet and the q-axis-side end portion of the magnet insertion hole. The permanent magnet further includes: a first communication portion communicating the d-axis-side end portion with the q-axis-side end portion; and a second communication portion communicating the d-axis-side end portion with the q-axis-side end portion.

A rotor for a rotary electric machine includes a rotor core in which a plurality of magnetic pole portions is provided. Each of the magnetic pole portions includes: a magnet insertion hole into which a permanent magnet is inserted. A d-axis-side space portion is provided inside the magnet insertion hole between the d-axis-side end portion of the permanent magnet and the d-axis-side end portion of the magnet insertion hole, and a q-axis-side space portion penetrating in the axial direction is provided inside the magnet insertion hole between the q-axis-side end portion of the permanent magnet and the q-axis-side end portion of the magnet insertion hole. The permanent magnet further includes: a first communication portion communicating the d-axis-side end portion with the q-axis-side end portion; and a second communication portion communicating the d-axis-side end portion with the q-axis-side end portion.

An embodiment provides a stator comprising a stator core having a plurality of teeth and coils wound around the teeth, wherein the tooth includes a body around which the coil is wound and a shoe connected to the body, the shoe includes a plurality of grooves and a curvature center of the inner peripheral surface of the shoe is the same as the center of the stator core.

A motor includes a stator having a winding, and a rotor. The rotor rotates by receiving a rotational magnetic field generated by drive current supplied to the winding. The winding includes a first winding and a second winding, the first and second windings both being excited at the same timing by the drive current. The first winding and the second winding are connected in series. The rotor includes a first pole section and a second pole section. The second pole section faces the second winding at the rotation position of the rotor at which the first pole section faces the first winding. The magnetic force exerted on the stator by the second pole section is weaker than that exerted by the first pole section.

A rotor of a rotary electric machine includes a first magnet and a fourth magnet whose magnetic fields are oriented in radial directions of a stator, and a second magnet and a third magnet whose magnetic fields are oriented in circumferential directions of the stator. Teeth portions of the stator each include a base portion that protrudes in a radially inward direction of a yoke portion, a flange portion that is wider than the base portion, and an expanding portion interposed between the base portion and the flange portion. An angle of intersection between the base portion and the expanding portion is 108° to 130°. A distance (thickness) from an inner circumferential side end part to an outer circumferential side end part of the flange portion is 0.2 mm to 2.0 mm.