| 主权项 |
1. A sealing unit for rolling bearings of wheel hub assemblies, adapted to be inserted between a first and a second member in relative rotation for fluid-sealingly insulating from an external environment an annular cavity defined between the first and second members, the sealing unit having a symmetry axis (A) and comprising:
a first annular shield angularly integrally constrainable to the first member by a respective sleeve portion for rotating with the first member about the symmetry axis (A) and defining an axially outer shield of the sealing unit with respect to the annular cavity; a second annular shield angularly integrally constrainable to the second member, coaxial to the first shield, by a respective sleeve portion, and defining an axially inner shield of the sealing unit with respect to the annular cavity; the second annular shield and the first annular shield defining between them an annular chamber delimited on opposite sides, in the radial direction, by the sleeve portions, and, in the axial direction, by respective flange portions of the first and second shields arranged reciprocally facing, the flange portion of the first shield delimiting the annular chamber towards the external environment (E); and a sealing ring integrally carried by the second annular shield and provided with at least a first and a second annular lip that extend axially and radially projecting from the flange portion of the second shield and towards the flange portion of the first shield, inside the annular chamber; wherein i) the first and second lips are arranged in sequence in a radial direction inside the annular chamber and cooperate with the flange portion of the first shield without touching it, and define a first dynamic labyrinth seal with the flange portion of the first shield and inside the annular chamber; ii) the first shield integrally supports a third annular lip which extends projecting from the first shield towards the first and the second lip without touching them, for defining a second dynamic labyrinth seal; and wherein iii) the first dynamic labyrinth seal is oriented radially, while the second dynamic labyrinth seal is oriented perpendicularly to the first dynamic labyrinth seal; iv) the first dynamic labyrinth seal extends along the whole radial extension of the first annular lip; v) the first and the third annular lip are shaped as a lower case U and a free end edge of the third lip is facing towards the first lip and is arranged, in a radial section, in a position immediately below and close to the first lip; vi) the free edge of the third lip and an extrados portion of the first lip facing toward the sleeve portion of the first shield being delimited by respective flat surfaces directed parallel to each other and to the symmetry axis (A) such as to define there between the second dynamic labyrinth seal. |
