means of bearing 9 on shaft 2 after oil has been introduced into the central cavity 43 of the bearing in operation the oil which leaves the end of the bearing is projected by centrifugal force and passing through the indentations 47 of washer 45 accumulates in cavity 48 where it is in contact with the bearing it is apparent that by doing away with the conventional square flanges considerable economy in material a reduction in weight and a reduction in the radial dimension are achieved and these advantages are in no way obtained to the detriment of the performances of the fan which result essentially from the peripheral feed of the fan blade unit so from the diameter thereof which has in no ways been modified besides these advantages in material weight and radial size of this fan with respect to conventional flange construtions a reduction in the axial dimension is obtained more especially by increasing the number of connecting arms which allows their section to be reduced particularly in the axial direction this advantage of the arms is added to that by which these arms dispense with the need at least on one side of the apparatus for the addition of a projection grid although the dimension of arms 5 is reduced in the axial direction the dimension of their section in the tangential direction is still further reduced as shown in the cut back 5b fig2 which confers on this arm an axial fin shape which serves as a honeycomb rectifier and improves the efficiency the arms are in fact situated in the air output face.