The invention provides a power
system assembly for two-speed electric vehicles. The power
system assembly for two-speed electric vehicles comprises an electromotor, a single-row planetary
gear train, a
synchronizer, a single reduction final drive, a compensating gear, a
magnet brake and a housing, wherein the
stator of the electromotor is fixed inside the housing; a rotor is connected with one side of a rotor shaft; the other side of the rotor shaft is arranged inside the housing in a penetrating manner through a bearing; the single-row planetary
gear train comprises a central gear, a
planet carrier and more than two planetary gears; the single reduction final drive comprises a small main reducing gear and a big main reducing gear which are meshed with each other; the
synchronizer comprises a first gear synchronous lock ring, a second gear synchronous lock ring, a meshing sleeve and a meshing sleeve seat. According to the invention, the technology of integrated structural design is adopted, so that the highly
integrated design and the application of the motor, the transmission and the compensating gear is realized; the integration of the electrically-driven
system becomes more obvious; the volume and the weight of the electrically-driven system are effectively reduced; the mounting is enabled to be more convenient; the two-gear speed change is adopted, so that the efficiency and the torque of the electromotor are improved.