Manufacturing method of permanent magnet motor rotor

The invention discloses a manufacturing method of a permanent magnet motor rotor. The permanent magnet motor rotor comprises a rotor body which is laminated with rotor lamination sheets. Permanent magnet grooves are formed in the rotor body. Permanent magnets are arranged in the permanent magnet grooves. The method is characterized by comprising the steps of preparing permanent magnet powdery material; in room temperature, making the permanent magnet grooves of the rotor body filled with the permanent powdery material; conducting heating once or for multiple times to the rotor body filled with the permanent magnet powdery material to sinter the permanent magnet powdery material, after the sintering, cooling the rotor body and permanent magnet powdery material together, at the same time, achieving the heat treatment of the rotor body, and the like. According to the manufacturing method of permanent magnet motor rotor, in the sintering process, the contact surfaces between permanent magnets and the permanent magnet grooves are tightly bonded, makes the permanent magnets fixedly arranged in the permanent magnet grooves. At the same time, in the process of one time or multiple times of heating, thermal insulating and cooling, the stability of metallurgical structure of the rotor body and the permanent magnets is increased, the internal stress of the rotor body is reduced, and the mechanical performance and electromagnetic performance of the rotor are enhanced.