An assembly providing a first annular shield including a sleeve portion integral with a rotating member and with a flange portion, which radially extends to protrude from the first sleeve portion; a second annular shield having a sleeve portion integral with a stationary member and with a flange portion that radially extends to protrude on the opposite side of the sleeve portion of the first shield and facing the flange portion; and an annular seal, which the flange portion of the first shield ends with an L-shaped annular portion that protrudingly radially and axially extends out of an annular gap delimited between the rotating and stationary members to define an L-shaped channel in radial section having constant width and forming a first labyrinth seal; the channel leads into an annular recess, delimited between the second shield and a first lip of the annular seal without contacting the first shield.