Patent attributes
An axial flow fan is provided. The axial flow fan includes an impeller and a fan frame. The impeller has a maximum outer diameter. The fan frame includes a first body and a second body. The first body includes a plurality of connecting elements and a base. The connecting elements are connected to the base. The second body is a hollow body, and used for disposing around the impeller. The second body includes a flow passage having a minimum inner diameter. The minimum inner diameter of the flow passage is not larger than the maximum outer diameter of the impeller. Therefore, the size of the second body does not restrict the maximum outer diameter of the impeller, and the shape of the impeller and the shape of the fan frame can be designed flexibly according to the practical demand.
