Turbine engine rotor retaining methods
A rotor stack is assembled to a turbine engine shaft. A force is exerted to at least one of the rotor stack and the shaft to at least one of place the shaft under tension and place the rotor stack under compression. One or more retainer segments are inserted into a rebate in the shaft. The exerted force is released to permit the rotor stack to bear against the retainer segments.
1. A method comprising:
assembling a rotor stack to a turbine engine shaft;
exerting force to at least one of the rotor stack and the shaft;
inserting at least two retainer segments into a rebate in the shaft, the segments being separate pieces; and
releasing the exerted force to permit the rotor stack to bear against the retainer segments.
2. The method of claim 1 wherein the exerting comprises:
exerting force between the rotor stack and the shaft to place the shaft under tension and the rotor stack under compression.
3. The method of claim 2 wherein said one or more retainer segments are exactly two retainer segments.
4. The method of claim 3 wherein each of the retainer segments is under 180° of arc.
5. The method of claim 1 wherein each of the retainer segments has an arc span effective to leave gaps between adjacent segment ends so that the segments do not interfere with each other.
6. The method of claim 5 wherein:
the segment ends are circumferential ends.
7. The method of claim 1 further comprising:
installing a collar at least partially surrounding the retainer segments so as to secure the retainer segments in place against radial displacement.
8. The method of claim 7 further comprising:
longitudinally restraining movement of the collar by a bearing support element.
9. The method of claim 7 wherein:
the installing of the collar consists of a translation.
10. The method of claim 7 wherein:
the installing of the collar does not involve threaded engagement of the collar.
11. The method of claim 2 wherein:
the exerting compresses the rotor stack with a force in excess of 50 kN.
12. The method of claim 2 wherein:
the releasing leaves the rotor stack under a precompression force of at least 50 kN.
13. The method of claim 2 , wherein:
the assembling includes interference fitting an end portion of at least one spacer element within a portion of at least one rotor disk.
14. The method of claim 2 wherein the rebate is radially outwardly open and a forward surface of the rebate engages the retainer segments to resist a force from the rotor.
15. The method of claim 2 further comprising:
running the shaft and rotor, a force transmitted across the retainer segments between the shaft and rotor increasing with speed of the rotation.
16. The method of claim 2 further comprising:
rotating the shaft and rotor, a force transmitted across the retainer segments between the shaft and rotor essentially continuously increasing with speed of the rotation from a static condition to an at-speed condition.
17. The method of claim 1 wherein the exerting force to at least one of the rotor stack and the shaft comprises at least one of:
placing the shaft under tension; and
placing the rotor stack under compression.
18. The method of claim 17 wherein:
the releasing leaves the rotor stack under a precompression force of at least 50 kN and the shaft under a pretension force of at least 50 kN.
19. The method of claim 1 wherein:
the releasing leaves the rotor stack under a precompression force of at least 50 kN and the shaft under a pretension force of at least 50 kN.
20. The method of claim 1 wherein:
the exerting force comprises compressing the rotor stack.
21. The method of claim 1 wherein:
the exerting is before the inserting and the releasing is after the inserting.
22. The method of claim 1 wherein:
the releasing causes the rotor stack to bear against the retainer segments.