Motor rotor, motor, electric drive assembly system and vehicle

The present disclosure relates to a motor rotor (100) comprising a motor shaft (10) rotatable about an axis of rotation (X), comprising a first end (10a) and a second end (10b) opposite the first end; the motor shaft (10) passes through the center of the rotor lamination assembly (20) and is rotationally fixed with the rotor lamination assembly (20); and the fixing piece (30) is fixed to the motor shaft (10) at the second end (10b). The motor shaft (10) comprises a central hole (11) arranged at the first end (10a) and a first radial hole (12) communicating with the central hole (11). The fixing piece (30) comprises a second radial hole (31) communicated with the outer surface of the fixing piece (30). A groove (1) communicated with the first radial hole (12) and the second radial hole (31) is arranged at the interface area of the motor shaft (10) and the rotor lamination assembly (20). 本公开涉及一种电机转子(100)，其包括电机轴(10)，能够绕旋转轴线(X)旋转，包括有第一端(10a)以及与所述第一端相对的第二端(10b)；转子叠片组件(20)，所述电机轴(10)从转子叠片组件(20)的中心穿过并与所述转子叠片组件(20)旋转固