Method of assembling a turbomachine
View Patent ↗A method of assembly of a turbomachine that includes a first module and a second module with a second shaft assembled by a bearing, the bearing including an outer ring shrink-fitted inside a journal integral with the first module and an inner ring integral with the second shaft. The second module is assembled on the first module by engagement of the second shaft, with the inner ring, inside the journal. The method includes a step of inserting the second module in the first module up to a determined distance such that the first and second modules are only partially assembled. The second shaft is centered with respect to the journal, the centering being controlled on the basis of measuring distance deviations with respect to a reference on the journal. The journal is expanded by heating its outer surface. After the step of expanding, the second module is displaced inside the first module so as to complete the assembly. This displacement step is started based on a predetermined temperature.
1. A method of assembly of a turbomachine comprising at least a first module and a second module with a second shaft to be assembled by a bearing, said bearing comprising an outer ring shrink-fitted inside a journal integral with the first module and an inner ring integral with the second shaft, according to which the second module is to be assembled on the first module by engagement of the second shaft, with said inner ring, inside the journal comprising said outer ring, said method of assembly comprising the following steps:
inserting the second module in the first module up to a determined distance such that said first and second modules are only partially assembled,
centering the second shaft with respect to the journal, said centering being controlled based on measuring distance deviations with respect to a reference on the journal,
expanding the journal by heating an outer surface of said journal after said inserting and centering steps, and
after said step of expanding, displacing said second module inside said first module, said displacing being carried out in translation so as to complete the assembly of said first and second modules, wherein said displacing is started based on a predetermined temperature produced by said heating of the outer surface of the journal.
2. The method as claimed in claim 1 , the engine being a double-body engine, wherein the first module is the high pressure (HP) body and the second module is the low pressure (LP) turbine, and the second shaft being the LP turbine shaft.
3. The method as claimed in claim 2 , wherein the first module comprises a first shaft, the journal being in its extension and integral said first shaft.
4. The assembly method as claimed in claim 1 , further comprising a step, prior to the step of inserting the second module in the first module, of heating the journal and shrink-fitting the outer ring in said journal.
5. The method as claimed in claim 4 , further comprising putting into position on the journal an annular heater between the step of inserting and the step of expending the journal by heating.
6. The method as claimed in claim 5 , wherein said predetermined temperature is the temperature of the journal or of the outer ring, further comprising measuring said temperature of said journal or of the outer ring during said step of expending, and controlling the heating until said predetermined temperature is reached.
7. The method as claimed in claim 6 , wherein starting said step of displacing the second module is carried out only after said temperature of said journal or of the outer ring and the distance deviations with respect to the journal are within predetermined limits.
8. The method as claimed in claim 1 , wherein said heating is performed by exposing said outer surface of said journal to heated gas from a plurality of heaters disposed outside said journal.
9. The method as claimed in claim 8 , wherein said measuring of the distance deviations during said step of centering is performed with a plurality of lasers disposed outside said journal.