| 摘要 |
A fan is disclosed comprising an electric drive motor having a shaft with an impeller coaxially disposed thereon, the impeller configured to suck axially and to blow with radial directional components and including a hub which is turned down over the motor, the hub having a rearward broad end that is turned away from the flow and presenting an outer generated surface that is symmetrical in rotation with reference to the motor axis, the outer generated surface being widened like a funnel in the direction of flow and inwardly defining an annular flow passage, and wherein blades are fastened to the hub along the generated surface. Further, in the disclosed fan the outer edges of the blades extend along a surface of rotation that is coaxial to the axis of the motor, the surface of rotation being constantly widened in the flow direction like a funnel, the widenings of the generated surface and the surface of rotation at least preponderantly having an opening angle that is less than 90 DEG , the generated surface and surface of rotation being continuous and wherein the flow cross section in the flow passage between the surface of rotation and the generated surface increases in the direction of flow. |
