Axial fan

Abstract

The invention relates to an axial fan for delivering cooling air, in particular for an internal combustion engine of a motor vehicle, comprising fan blades which are fastened to a hub and which have a pressure side and a suction side and a trailing edge and a blade depth, on the pressure side of which fan blades is arranged a hub ramp which rises counter to the direction of rotation of the axial fan, wherein the trailing edge has an outer region situated radially outside the hub ramp and has an inner region situated radially within the hub ramp.

1 . An axial fan for delivering cooling air, in particular for an internal combustion engine of a motor vehicle, comprising fan blades which are fastened to a hub and which have a pressure side and a suction side and a trailing edge and a blade depth, on the respective pressure side of which fan blades is arranged a hub ramp which rises counter to the direction of rotation of the axial fan, wherein the trailing edge has an outer region situated radially outside the hub ramp and has an inner region situated radially within the hub ramp, wherein the trailing edge has, in the outer region radially outside the hub ramp, a profile which continues in substantially unchanging fashion radially inward across the radial position of the hub ramp into the inner region, and which, in the radially innermost region, runs toward the hub. 
     
     
         2 . The axial fan as claimed in  claim 1 , wherein the radially innermost region is the radially inner component of the radius of the radially inner region. 
     
     
         3 . The axial fan as claimed in  claim 2 , wherein the component is approximately one third, approximately one quarter or preferably less than approximately one fifth of the radius of the inner region of the trailing edge. 
     
     
         4 . The axial fan as claimed in  claim 1 , wherein the blade depth in the inner region corresponds to the blade depth in the outer region. 
     
     
         5 . The axial fan as claimed in  claim 1 , wherein the trailing edge is formed as a substantially straight edge in the outer and in the inner region but not in the innermost region. 
     
     
         6 . The axial fan as claimed in  claim 1 , wherein the trailing edge, in the innermost region, is rounded and merges into the hub. 
     
     
         7 . The axial fan as claimed in  claim 1 , wherein the trailing edge, in its radially innermost region, merges via a rounding into a free edge of the hub ramp. 
     
     
         8 . The axial fan as claimed in  claim 1 , wherein air-guiding elements in the form of stabilizers are arranged on the suction side of the fan blades. 
     
     
         9 . The axial fan as claimed in  claim 8 , wherein the stabilizers extend as far as into the inner region of the trailing edges. 
     
     
         10 . The axial fan as claimed in  claim 1 , wherein the hub is in the form of a hub ring with an axial extent which is significantly smaller than the fan blade depth. 
     
     
         11 . The axial fan as claimed in  claim 1 , wherein the axial fan has a hub ratio D i /D a  of greater than 42%, wherein D i  is the outer diameter of the hub and D a  is the outer diameter of the fan blades. 
     
     
         12 . The axial fan as claimed in  claim 1 , wherein a liquid friction clutch is arranged within the hub ring and is fixedly connected to the hub ring. 
     
     
         13 . The axial fan as claimed in  claim 1 , wherein the fan blades are angled in the direction of their blade root, wherein the angled region of the fan blade is at least partially drawn downward onto the hub or the hub ring.