Fan assembly for air treatment systems for vehicles

Fan assembly for air treatment systems for vehicles, comprising a support case (12) formed by a first injection moulded plastic material, having a seat (14) in which is housed and electric motor (32) bearing a fan (38). The assembly comprises at least a support element (50) and/or a sealing element (46) and/or a fastening element (52) formed by over-injecting a second material, softer than said first material, on at least a portion of said seat (14).