Methods, systems, and mechanical and electromechanical arrangements for field-weakening of an electric machine that utilizes permanent magnets are disclosed herein. One rotor assembly for an electric motor includes a rotor body that moves with respect to a central axis, the rotor body having a core and a number of permanent magnets that move with the rotor body, and the rotor body also having a number of movable field-weakening magnetic materials that move with respect to the permanent magnets and to the central axis.

An apparatus for assembling a permanent magnet motor rotor includes a first-end positioning assembly, a plurality of connectors, and a second-end positioning assembly. The first-end positioning assembly is utilized to fix a first-end rotor core. The second-end positioning assembly is utilized to fix a second-end rotor core. The connectors are utilized to connect and fix the first-end positioning assembly with the second-end positioning assembly. Each first longitudinal axis of each first positioning element of the first end positioning assembly is different from each second longitudinal axis of each second positioning element of the second end positioning assembly. In addition, a method for assembling a permanent magnet motor rotor is also provided.

A rotor assembly comprising rotatable element having a set of first permanent magnets and a set of second permanent magnets alternately circumferentially spaced about the rotatable element. The first permanent magnets are evenly spaced from each other, the second permanent magnets are evenly spaced from each other, and each second permanent magnet is disposed between and unevenly spaced from a respective pair of immediately adjacent first permanent magnets.

A rotor assembly comprising rotatable element having a set of first permanent magnets and a set of second permanent magnets alternately circumferentially spaced about the rotatable element. The first permanent magnets are evenly spaced from each other, the second permanent magnets are evenly spaced from each other, and each second permanent magnet is disposed between and unevenly spaced from a respective pair of immediately adjacent first permanent magnets.

The present invention may provide a motor including a rotor and a stator disposed to correspond to the rotor, wherein the rotor includes a rotor core and a magnet disposed on the rotor core, the rotor core includes a first region in which the magnet is disposed, the first region of the rotor core includes two grooves, one of the two grooves is disposed at a position corresponding to one end region of the magnet, and the other one of the two grooves is disposed at a position corresponding to the other end region of the magnet.

An apparatus for assembling a permanent magnet motor rotor includes a first-end positioning assembly, a plurality of connectors, and a second-end positioning assembly. The first-end positioning assembly is utilized to fix a first-end rotor core. The second-end positioning assembly is utilized to fix a second-end rotor core. The connectors are utilized to connect and fix the first-end positioning assembly with the second-end positioning assembly. Each first longitudinal axis of each first positioning element of the first end positioning assembly is different from each second longitudinal axis of each second positioning element of the second end positioning assembly. In addition, a method for assembling a permanent magnet motor rotor is also provided.

A rotor includes: a shaft; a rotor back yoke having a through hole defined in an axial center through which the shaft is inserted, the rotor back yoke being integrally and rotatably connected to the shaft; and magnets fixed to an outer peripheral surface of the rotor back yoke, the plurality of magnets being disposed with magnetic poles of different polarities being arranged alternately along a circumferential direction. The rotor back yoke includes a plurality of first cutout portions provided at predetermined intervals in the circumferential direction and extending from an inner peripheral surface of the rotor back yoke outward in a radial direction. Each of the plurality of first cutout portions extends along an axial direction, from one end surface to the other end surface of the rotor back yoke.

A rotor includes: a shaft; a tubular rotor core; and a plurality of magnets. The shaft extends along a center axis. The rotor core surrounds the shaft. The plurality of magnets is disposed outside the rotor core in a radial direction and is aligned in a circumferential direction. A plurality of first recessed portions recessed outward in the radial direction is aligned in the circumferential direction in an inner surface of the rotor core in the radial direction. Each of the first recessed portions overlaps each of the magnets in the radial direction.

A rotor assembly for a motor includes at least one magnet, a magnet support having an end region, a rotor shaft and an over-molded body affixed to the at least one magnet and the magnet support. The over-molded body includes a first end and a second end. The rotor shaft may be disposed proximate to the first end of the over-molded body and the second end of the over-molded body is proximate to the end region of the magnet support.

A rotor structure of a synchronous motor includes: a stator; and a rotatable rotor on the inner side of the stator, in which the rotor includes: a rotor core fixed to a rotary shaft; and a permanent magnet on the outer side of the rotor core, the permanent magnet on the outer side of the rotor core includes a main magnet and an auxiliary magnet, the auxiliary magnet is provided in contact with the outer side of the rotor core, and the main magnet is provided in contact with the outer side of the auxiliary magnet.