Turbo-jet engine with fan integral with a drive shaft supported by first and second bearings

1. A turbo-jet engine comprising:

a fixed structure;

a fan rotor fixed to a drive shaft supported by a first bearing and a second bearing;

an axial retaining device configured to cooperate with the fixed structure and mounted rigidly to the drive shaft; and

a structural flange on which the second bearing is fixed,

wherein the axial retaining device is configured to form an emergency bearing and includes a retaining disk mounted on the drive shaft, the retaining disk configured to cooperate with a stop disk on the flange to axially retain the fan and further configured to cooperate with a longitudinal sleeve of flange to form a bearing surface.

2. The turbo-jet engine as recited in claim 1 , wherein the axial retaining device is arranged to transmit axial stresses directly to the drive shaft.

3. The turbo-jet engine as recited in claim 2 , wherein the second bearing includes an inner ring, an outer ring and rollers mounted between said inner and outer rings, the retaining disk includes radial teeth axially bearing upon teeth of the drive shaft and locked in rotation by longitudinal teeth of the inner ring of the second bearing.

4. The turbo-jet engine as recited in claim 3 , wherein the outer ring has a radially exterior surface configured to mate with a housing connected to the flange, and the radially exterior surface and housing mate together as a ball joint.

5. The turbo-jet engine as recited in claim 1 , wherein the axial retaining device includes an upstream bearing surface, and the structural flange includes a downstream bearing surface against which downstream bearing surface the upstream bearing surface slides in the event of a decoupling of the first bearing from the fixed structure, and downstream is a direction taken traveling from the first bearing toward the second bearing along an axis of the turbo-jet engine, and upstream is a direction opposite the downstream direction.

6. The turbo-jet engine recited in claim 5 , wherein one of the upstream and downstream bearing surfaces is spherical.

7. The turbo-jet engine recited in claim 5 , wherein the retaining disk is upstream of the second bearing.

8. The turbo-jet engine as recited in claim 1 , wherein the retaining disk includes a radial bearing surface configured to slide against an interior annular surface of the flange while the first bearing is in a state decoupled from the fixed structure.

9. The turbo-jet engine as recited in claim 8 , wherein the retaining disk includes an axial bearing surface configured to slide against a conical surface of the flange while the first bearing is in the state decoupled from the fixed structure.

10. The turbo-jet engine as recited in claim 1 , further comprising first shearing screws connecting the flange to the first bearing via a first bearing support.

11. The turbo-jet engine as recited in claim 10 , further comprising second shearing screws connecting the second bearing to the flange and which are configured to shear to allow the retaining disk to make contact with the flange.

12. The turbo-jet engine as recited in claim 11 , wherein the second bearing includes rollers configured to permit axial movement of the shaft relative to the fixed structure after the second shearing screws break, but before the retaining disk makes contact with the flange.

13. The turbo-jet engine as recited in claim 1 , wherein the retaining disk is mounted in an annular groove of the drive shaft.

14. The turbo-jet engine as recited in claim 1 , wherein the retaining disk is mounted on the drive shaft downstream of the flange when downstream is a direction taken traveling from the first bearing toward the second bearing along an axis of the turbo-jet engine.