Rotary electrical machine

A rotary electrical machine of a variable field type configured to change a field magnetic flux, the rotary electrical machine comprising:

• a stator including stator windings and a stator core;
• and
• a rotor provided in the stator to be surrounded by the stator and to be rotatable around an axis, the rotor comprising:
• a shaft provided to be rotatable around the axis;
• a rotor core mounted on the shaft to be relatively rotatable with respect to the shaft around the axis, the rotor core having an axial length along the axis approximately same as an axial length of the stator core along the axis;
• first permanent magnets disposed on the rotor core;
• a cylindrical member fixed to an outer circumference of the shaft,
• second permanent magnets fixed to an outer circumference of the cylindrical member so as to have different polarities alternately in a rotational direction, and having a same number as a plurality of magnetic pole parts each formed between the plurality of first permanent magnets on the rotor core, the second permanent magnets facing the magnetic pole parts in a radial direction, and
• wherein the rotor core is held with respective to the shaft at an angular position where the magnetic pole part and the second permanent magnet which mutually have different polarities face each other in the radial direction,
• wherein the rotor is configured to change a relative angle between the magnetic pole part and the second permanent magnet which mutually have different polarities depending on magnitude of a load torque.