Rotor device of permanent magnet synchronous motor and manufacturing method

The invention discloses a rotor device of a permanent magnet synchronous motor and a manufacturing method. The rotor device comprises a die-casting upper die, a die-casting lower die, a die-casting middle sleeve, a false shaft child-mother key and a plurality of groove sample blocks, the die-casting lower die and the die-casting middle sleeve form an inner cavity, a dummy shaft child-mother key is arranged in a through hole of the die-casting lower die in the center of the inner cavity, and a plurality of groove sample block positioning grooves and a plurality of exhaust channels are arranged on the die-casting lower die around the dummy shaft child-mother key; the dummy shaft primary and secondary key is provided with a magnetic steel groove rotor punching sheet, one end of a first batch of the plurality of groove sample blocks respectively penetrates into a magnetic steel groove in the magnetic steel groove rotor punching sheet, the other end of the first batch of the plurality of groove sample blocks is in