Internal permanent magnet synchronous motor rotor structure

The utility model relates to an internal permanent magnet synchronous motor rotor structure, which comprises permanent magnets, rotor slots, a rotating shaft and a magnetic shielding sleeve of a motor rotor. The internal permanent magnet synchronous motor rotor structure is characterized in that the permanent magnets are divided into two parts at a 1/2 position of the length in magnetization direction to form a bell shape, one radial permanent magnet is disposed between two poles, and then two quasi-tangential permanent magnets and a radial permanent magnet form a U-shaped magnetic circuit mixed rotor structure in one pole, partitioning magnetic bridges are arranged between a starting cage and the permanent magnet slots, and between the quasi-tangential permanent magnets and the radial permanent magnets. Because relative magnetic permeability of the permanent magnets are nearly equal to that of air, existence of the radial permanent magnets enables magnetic flow generated by the permanent magnets not to pass through a yoke portion of the motor rotor and the motor rotating shaft to form flux leakage circuits, but pass through a rotor yoke, a rotor tooth, an air clearance, a stator tooth, a stator yoke, a stator tooth, an air clearance, a rotor tooth and a rotor yoke and then return to the permanent magnets, thereby forming a main magnetic flow circuit. Besides, a magnetic shielding sleeve is saved between a rotor iron core and the rotating shaft.