A supporting assembly including a bearing, a bearing housing having an annular element housing and a base for fixing, and a cover for close fluid tight an opening of the housing element; the cover being cup-shaped and including an annular coupling portion to a radially outer lateral surface for housing the annular element. The coupling portion provided radially on the inside with at least a pair of teeth projecting radially towards the inside of the lid; the lateral surface of the annular element housing provided with an annular seat for the teeth of the lid, including: an annular groove disposed axially spaced with respect to a front edge of the housing element; axial grooves equal to the number of teeth present and that radially interrupt the front edge; and a bottom wall provided with a plurality of alternating troughs and projections arranged offset circumferentially with respect to the axial grooves.