Fan anti-foreign matter structure

1 . A fan anti-foreign matter structure, comprising a fan wheel and a fan frame, wherein:

said fan wheel comprises a fan hub, an interior space with an air outlet defined in said fan hub for the mounting of a rotating shaft, a plurality of fan blades surrounding an outer surface of said fan hub, an air diversion radiator plate mounted on a top surface of said internal space and surrounding the said rotating shaft mounted in said internal space, said air diversion radiator plate composing at least an airflow guide rib and an airflow guide ring, at least an air duct formed between at least one said airflow guide rib and said airflow guide ring, an air inlet slot formed on one side of said air duct to guide the air from said interior space to enter the respective said air duct, and an airflow turning curved surface formed on an opposite side of said air duct to squeeze and guide an airflow to enter the respective said air duct to discharge hot air outward and downward, so that a positive pressure is formed at the air outlet of said interior space relative to an external space to prevent dirty air containing dust, salt, etc. from the external space from entering said interior space of said fan hub;

said fan frame comprises an accommodating space, an axle seat, an axle seat disk, an axle seat bracket and a fan air outlet, said accommodating space accommodating said axle seat, said axle seat disk, said axle seat bracket and disposed in communication with said fan air outlet, said axle seat of said fan frame being used for assembling said fan wheel inside said accommodating space, a sleeve is protruded from said axle seat disk and used for assembly of said rotating shaft; and

wherein said axle seat disk in said axle seat is sealed, and after said fan wheel is assembled into said accommodating space of said fan frame, only a gap between said fan hub and said axle seat disk of said fan frame or a gap between said fan hub and a circuit board on said axle seat disk (that is, the air outlet of the interior space inside the fan hub) is left, so that when a fan rotates, the air outlet of said interior space inside said fan hub forms a positive pressure relative to the external space to prevent dirty air containing dust, salt, etc. from the external space from entering said interior space of said fan hub to cause the fan to stop running.

2 . The fan anti-foreign matter structure as claimed in claim 1 , wherein said air diversion radiator plate comprises said airflow guide ring surrounding said rotating shaft and a plurality of said airflow guide ribs; a wall below said airflow guide ring in said interior space of said fan hub is provided with a rotor magnet; an inner peripheral surface of said airflow guide ring aligned with the inner peripheral surface of said rotor magnet and forms an escape space for the hot air to flow smoothly between an outer silicon steel sheet; each said airflow guide rib of said air diversion radiator plate is connected to said airflow guide ring so that at least one space from narrow to wide and then to narrow is formed; each said airflow guide rib extends from the outside of said rotating shaft pivot seat in a parabolic path to the inner peripheral surface of said airflow guide ring and is connected at an approximate tangent to form at least one said air duct, so that said air inlet slot that guides external airflow to enter is formed in the space from narrow to wide on one side of said air duct close to said rotating shaft pivot seat, and said airflow turning curved surface is formed at a narrowest space in the space from wide to narrow on the opposite side of said air duct to guide the airflow to be squeezed downward and discharge outward and to generate the positive pressure at the air outlet of the interior space of said fan hub relative to the external space.

3 . A fan anti-foreign matter structure, comprising a fan wheel and a fan frame, wherein:

said fan wheel comprises a fan hub, an interior space, a plurality of fan blades surrounding an outer surface of said fan hub, a rotating shaft bearing seat set in said interior space, an air diversion radiator plate mounted on a top surface of said internal space and surrounding said rotating shaft bearing seat, said air diversion radiator plate comprising at least an airflow guide rib and an airflow guide ring, at least an air duct formed between said at least one said airflow guide rib and said airflow guide ring, an air inlet slot formed on one side of said air duct to guide an external airflow to enter said air duct, and an airflow turning curved surface formed on an opposite side of said air duct to guide the external airflow to be squeezed and discharged outward;

said fan frame comprises an accommodating space, an axle seat, an axle seat disk, an axle seat bracket and an air outlet, said accommodating space accommodating said axle seat, said axle seat disk, said axle seat bracket and disposed in communication with said air outlet, a sleeve set on said axle seat disk in said axle seat, a receiving space defined in said sleeve for assembly of said rotating shaft bearing seat of the fan wheel, a rotating shaft is protruded from said receiving space of said sleeve inside said axle seat for assembly of said rotating shaft bearing seat; and

wherein said axle seat disk in said axle seat is sealed, and after said fan wheel is assembled into said accommodating space of said fan frame, only a gap between said fan hub and said axle seat disk of said fan frame or a gap between said fan hub and a circuit board on said axle seat disk (that is, the air outlet of the interior space inside said fan hub) is left, so that when a fan rotates, the air outlet of the interior space inside said fan hub forms a positive pressure relative to an external space to prevent dirty air containing dust, salt, etc. from the external space from entering said interior space of said fan hub to cause the fan to stop running.

4 . The fan anti-foreign matter structure as claimed in claim 3 , wherein said air diversion radiator plate comprises said airflow guide ring surrounding said rotating shaft bearing seat and a plurality of said airflow guide ribs; a wall below said airflow guide ring in said interior space of said fan hub is provided with a rotor magnet; an inner peripheral surface of said airflow guide ring aligned with the inner peripheral surface of said rotor magnet and forms an escape space between an outer silicon steel sheet for hot air to pass through; each said airflow guide rib is connected to said airflow guide ring so that at least one space from narrow to wide and then to narrow is formed; each said airflow guide rib extends from the outside of a rotating shaft pivot seat in a parabolic path to the inner peripheral surface of said airflow guide ring and is connected at an approximate tangent to form at least one said air duct, so that said air inlet slot that guides internal airflow to enter is formed in the space from narrow to wide on one side of said air duct, and said airflow turning curved surface is formed at a narrowest space in the space from wide to narrow on the opposite side of said air duct to guide an airflow to be squeezed downward and discharged outward and to generate the positive pressure at the air outlet of the interior space of said fan hub relative to an external space during rotation of the fan.

5 . The fan anti-foreign matter structure as claimed in claim 4 , wherein said escape space is formed between said rotor magnet and a plurality of outer silicon steel sheets, and a stator silicon steel sheet set and said circuit board are provided with a protective layer selectively formed by coating or glue filling to isolate air, dust and water.