Rotor assembly and brushless dc motor comprising the same

A rotor assembly, comprising:

• a) a permanent magnet (1);
• b) a rotor core (2), the rotor core (2) comprising:
• an annular ring (22) comprising a central axial bore (21), a plurality of magnetic induction blocks (23),a radial recess (24), an end surface, and a bottom surface, each magnetic induction block comprising a through hole (27);
• c) a magnetic loop (4);
• d) a magnetic loop bracket (3);
• e) an end plate (35) comprising an end surface;
• f) a base plate (36);
• and
• g) a first connecting column (37);
• wherein
• the magnetic induction blocks (23) protrude outward from an outer side of the annular ring (22);
• the radial recess (24) is formed between every two adjacent magnetic induction blocks (23) for mounting the permanent magnet (1);
• the end plate (35) and the base plate (36) are disposed on the end surface and the bottom surface of the rotor core (2) by injection molding, respectively;
• the first connecting column (37) passes through the through hole (27) and connects the end plate (35) and the base plate (36) to form a whole body;
• the end surface of the end plate (35) protrudes upward to form the magnetic loop bracket (3);
• and
• the magnetic loop (4) is disposed on the magnetic loop bracket (3).