Electric Fan

Abstract

An electric fan has an electric motor driving an axial fan. The fan has a cup-shaped hub, with a front wall, and a side wall from which there extends a plurality of outer blades. The motor has an outer rotor including a rotor cap to which the front wall of the hub is attached. From the inner surface of the hub and/or from the outer surface of the rotor cap, there extend protruding formations which, when the fan performs an oscillation of predetermined extent with respect to the rotor, impact the rotor cap and/or the hub, limiting the extent of the oscillation of the fan with respect to the rotor.

1 . An electric fan comprising:
 an electric motor including an external rotor and an internal stator; and   an axial fan including a substantially cup-shaped central hub, with a front wall, facing and connected to the rotor, and a side wall which surrounds the rotor, and from which there extends a plurality of outer blades,   wherein protruding formations extend from the inner surface of the hub of the fan and/or from the outer surface of the rotor, and   wherein, when the fan performs an oscillation of predetermined extent with respect to the rotor, the protruding formations impact the rotor and/or the hub, limiting the extent of the oscillation of the fan with respect to the rotor.   
     
     
         2 . The electric fan of  claim 1 , wherein the rotor of the electric motor has a cap which extends inside the hub of the fan close to the front wall of the hub to which it is connected by means of one or more connecting devices including respective elastic vibration dampers. 
     
     
         3 . The electric fan of  claim 2 , wherein the or each of the connecting devices comprises an annular damper member of elastic material arranged in a through-opening of the hub, and through which a fastening member passes to fasten the hub to the cap of the rotor. 
     
     
         4 . The electric fan of  claim 3 , wherein the elastic material is an elastomeric material. 
     
     
         5 . The electric fan of  claim 3 , wherein between each damper member and the corresponding fastening member, there is a tubular element of substantially rigid material. 
     
     
         6 . The electric fan of  claim 5 , wherein the substantially rigid material is a metal material. 
     
     
         7 . The electric fan of  claim 5 , wherein the fastening member is a screw or bolt having an end head, and the rigid tubular element exhibits at one end a flange-like formation placed between the head of the corresponding screw or bolt and the damper member. 
     
     
         8 . The electric fan of  claim 1 , wherein the elastic damper member is substantially in the shape of a cylindrical ring, and exhibits an outer peripheral groove into which the edge of the through-opening of the hub is engaged. 
     
     
         9 . The electric fan of  claim 1 , wherein the hub of the fan is produced with a flexible material and the rotor of the motor has a cap which extends inside the hub of the fan close to the front wall of the hub, to which it is connected by means of one or more connecting devices.