Electric cooling fan

Abstract

An axial fan has a hub supporting blades. The hub is attached to a rotor of an electric motor at one or more points of connection by respective connecting devices. Each connecting device includes an annular damper, arranged in an opening of the hub, and through which a screw passes. Placed between the damper and the screw is a rigid element having one end resting against the rotor. The other end has an annular flange-like formation disposed between the damper and a head of the screw. The rigid element has an annular skirt which extends from the flange-like formation, around the damper, up to a preset distance from the hub of the fan, such that when the fan performs an oscillation greater than a predetermined extent, it impacts this skirt thereby limiting its oscillation.

1 . An electric cooling fan comprising:
 an electric motor including a rotor and a stator, and   an axial fan, with a central hub from which there extends a plurality of blades and which is connected to the rotor of the motor at one or more points of connection,   at the or each point of connection, the hub of the fan being connected to the rotor of the motor by means of a respective connecting device including a vibration damper, arranged in an opening of the hub, and through which a fastening member passes, there being placed between the damper and the corresponding fastening member a rigid element having one end resting against the rotor and the other end which has an annular flange-like formation resting against the damper at the side opposite the rotor;   wherein the rigid element has an annular skirt which extends from the flange-like formation, around the damper, to a preset distance from the hub, in such a way that when the fan performs, with respect to the rotor, an oscillation greater than a predetermined extent, the hub impacts the skirt thereby limiting the extent of the oscillation.   
     
     
         2 . The electric fan of  claim 1 , wherein the hub of the fan has a substantially cup-like shape, with a base wall connected with an annular side wall, and
 the rotor has a cap which extends inside the hub, close to the base wall to which it is connected by means of a plurality of connecting devices including respective vibration dampers.   
     
     
         3 . The electric fan of  claim 2 , wherein the annular side wall of the hub is at least approximately cylindrical. 
     
     
         4 . The electric fan of  claim 1 , wherein the vibration damper is annular. 
     
     
         5 . The electric fan of  claim 1 , wherein the damper is of elastic material. 
     
     
         6 . The electric fan of  claim 5 , wherein the elastic material is vulcanized rubber. 
     
     
         7 . The electric fan of  claim 1 , wherein the damper is substantially in the shape of a cylindrical ring, and has an outer peripheral groove into which the edge of the through-opening of the hub is engaged. 
     
     
         8 . The electric fan of  claim 1 , wherein the fastening member is a screw or bolt, having a head which presses on the flange formation of the rigid element.