Anti-pressure-relief structure for fan

An anti-pressure-relief structure for a fan comprising:

• a fan rotor including a hub, a shaft vertically downward extended from the hub, a plurality of blades radially outward extended from an outer wall surface of the hub, and an outer ring member connected to radially outer ends of the blades and
• a fan frame having an air inlet side, an opposite air outlet side, a passage defined between the air inlet and outlet sides, a base located in the fan frame at one end adjacent to the air outlet side and connected to an inner wall surface of the fan frame via a plurality of connecting members, a shaft cup vertically extended upward from the base, a stator assembly externally fitted around the shaft cup, and at least one bearing provided in the shaft cup;
• the fan rotor being rotatably connected to the bearing via the shaft, and the outer ring member of the fan rotor being mounted in the passage of the fan frame with a gap flow passage formed between the outer ring member and the fan frame;
• the outer ring member having an outer wall surface and the fan frame having a first inner wall surface extending axially parallel to the outer wall surface of the outer ring member and a second inner wall surface conically tapered from the air inlet side to the air outlet side;
• the outer wall surface of the outer ring member having a plurality of non-continuous raised sections provided thereon, and the first inner wall surface of the fan frame being provided with a plurality of non-continuous recessed sections that are staggered from those the plurality of non-continuous raised sections on the outer wall surface of the outer ring member wherein the non-continuous raised sections of the outer ring member correspond to and radially face the non-continuous recessed sections of the fan frame respectively to define a concave-convex complementary arrangement and so as to form an anti-pressure-relief zone;
• air flowing through the anti-pressure-relief zone being subject to swirls and impeded from flowing smoothly to achieve an anti-pressure relief effect.