Heat dissipation fan

1. A heat dissipation fan, comprising:

a housing;

a hub rotatably disposed in the housing; and

a blade structure disposed at a surrounding edge of the hub to be rotated with the hub, wherein the blade structure has a plurality of first blades and a plurality of second blades spaced apart from each other, wherein the first blades are connected to the hub, the second blades are not connected to the hub, when the heat dissipation fan is operated, the two adjacent first blades form a flow path, each of the second blades is located between the two adjacent first blades to form two divided paths branching from the flow path, in a direction away from the hub, one of the divided paths is continuously tapered, and the other of the divided paths is continuously expanded.

2. The heat dissipation fan of claim 1 , wherein the blade structure further comprises at least one ring body connected to the first blades and the second blades.

3. The heat dissipation fan of claim 2 , wherein the ring body is connected to a top of the first blades and a top of the second blades.

4. The heat dissipation fan of claim 2 , wherein the ring body passes through the first blades and the second blades to divide the flow path into layers along an axial direction, and the axial direction and an axis of rotation of the hub are consistent.

5. The heat dissipation fan of claim 2 , wherein the ring body is connected to a bottom of the first blades and a bottom of the second blades.

6. The heat dissipation fan of claim 1 , wherein the two divided paths comprise a first divided path, a second divided path, a first reduction section, and a second reduction section, the first reduction section is located at the first divided path, the second reduction section is located at the second divided path, and the first reduction section and the second reduction section are staggered from each other along a radial direction of the hub.

7. The heat dissipation fan of claim 1 , further comprising a pair of ring bodies respectively connected to the first blades and the second blades.

8. The heat dissipation fan of claim 7 , wherein the pair of ring bodies have different radial sizes.

9. The heat dissipation fan of claim 7 , wherein the second blades have a first end adjacent to the hub and a second end away from the hub, one of the pair of ring bodies is connected to the first blades and the second ends of the second blades, and the other of the pair of ring bodies is connected to the first blades and the first ends of the second blades.

10. The heat dissipation fan of claim 1 , wherein the blades further comprise a connecting portion connected between the first blades and the second blades, the connecting portion is connected between an end of the first blades away from the hub and an end of the second blades far from the hub, and the second blades are located between two adjacent first blades.

11. The heat dissipation fan of claim 10 , wherein the first blades, the second blades, and the connecting portion are formed by stamping and bending a metal plate.

12. The heat dissipation fan of claim 1 , wherein the heat dissipation fan is a centrifugal fan.

13. The heat dissipation fan of claim 1 , wherein the first blades and the second blades are metal blades.

14. A heat dissipation fan, comprising:

a housing;

a hub rotatably disposed in the housing; and

a blade structure disposed at a surrounding edge of the hub to be rotated with the hub, wherein the blade structure has a plurality of first blades and a plurality of second blades spaced apart from each other, wherein the first blades are connected to the hub, the second blades are not connected to the hub, when the heat dissipation fan is operated, the two adjacent first blades form a flow path, each of the second blades is located at the flow path and a width of the second blades gradually increases in a direction away from the hub, to form two divided paths branching from the flow path, and in the direction away from the hub, the two divided paths are continuously tapered.

15. The heat dissipation fan of claim 14 , wherein the blade structure further comprises at least one ring body connected to the first blades and the second blades.

16. The heat dissipation fan of claim 14 , wherein the two divided paths comprise a first divided path, a second divided path, a first reduction section, and a second reduction section, the first reduction section is located at the first divided path, the second reduction section is located at the second divided path, and the first reduction section and the second reduction section are located at the end of the first blade and at the end of the second blade.

17. The heat dissipation fan of claim 14 , wherein the heat dissipation fan is a centrifugal fan, and the first blades and the second blades are metal blades.