Method for partial disassembly of a bypass turbofan engine
A method and tooling for partial disassembly of a bypass turbofan engine wherein the longitudinal axis of the bypass turbofan engine remains generally horizontal during disassembly. The low pressure turbine module is removed with a low pressure turbine module horizontal removal tool. An extended bearing nut tool may be supported by a stabilization member and may remove a bearing nut. An extended high pressure turbine shaft stretching tool may stretch a high pressure turbine shaft to release a high pressure turbine shaft nut. An extended bearing pulling tool may be used to pull a bearing while the low pressure turbine shaft remains in place. A modified measurement bridge may be used to measure the position of certain components while the low pressure turbine shaft remains in place. A nozzle jig may be used to assemble nozzles and feather seals to create a nozzle module. And an arcuate datum may be used to make certain measurements from the aft end of the high pressure turbine shaft while the low pressure turbine shaft remains in place.
1. A method for partial disassembly of a bypass turbofan engine wherein the longitudinal axis of said bypass turbofan engine remains generally horizontal comprising the steps of:
connecting a first end of a low pressure turbine module horizontal removal tool to an aft end of a low pressure turbine module;
attaching a second end of said low pressure turbine module horizontal removal tool to a lift, said connection being generally above the center of gravity of said low pressure turbine module and said low pressure turbine module horizontal removal tool;
adjusting the upward force applied by said lift to counteract the force of gravity on said low pressure turbine module and said connected low pressure turbine module horizontal removal tool;
applying a generally horizontal force to said low pressure turbine module to separate it from said engine;
disengaging a bearing nut by positioning an extended bearing nut tool over a low pressure turbine shaft, said bearing nut tool engaging notches in said bearing nut and notches in a seal plate to impart a disengaging torque to said bearing nut;
positioning a measuring bridge adjacent the aft end of said bypass turbofan engine to be disassembled, said measuring bridge positioned adjacent said low pressure turbine shaft, said measuring bridge providing a stable datum from which measurements may be taken;
pulling a bearing by placing an extended bearing pulling tool around said low pressure turbine shaft, said extended bearing pulling tool applying a disengaging generally horizontal force to said bearing when said extended bearing pulling tool applies an opposing generally horizontal force to said low pressure turbine shaft; and
stretching a high pressure turbine shaft by placing an extended high pressure turbine shaft stretching tooling around said low pressure turbine shaft, a first portion of said extended high pressure turbine shaft stretching tool engaging said high pressure turbine shaft, a second portion of said extended high pressure turbine shaft stretching tooling engaging said seal plate, said extended high pressure turbine shaft stretching tooling transferring opposing generally horizontal forces to said high pressure turbine shaft and said seal plate to stretch said high pressure turbine shaft.
2. The method of claim 1 wherein:
said low pressure turbine horizontal removal tool permits rotational freedom of said low pressure turbine module about said module's longitudinal axis.
3. The method of claim 1 wherein:
said low pressure turbine horizontal removal tool has a pivot adapted to rotate said low pressure turbine module longitudinal axis from horizontal to vertical.
4. The method of claim 1 additionally comprising the steps of:
removing a nozzle assembly with a first stage nozzle assembly retaining tool, said nozzle assembly being comprised of a plurality of interlocked nozzle segments and feather seals, said first stage nozzle assembly retaining tool securing said nozzle assembly such that said plurality of nozzle segments and feather seals remain interlocked upon removal; and
placing said nozzle assembly in a nozzle assembly jig adapted to properly position said plurality of interlocked nozzle segments and feather seals, said nozzle assembly jig facilitating the interlocked construction of said nozzle assembly from said nozzle segments and feather seals.
5. The method of claim 1 additionally comprising the step of:
inserting a support between said high pressure turbine shaft and a component radially displaced from said high pressure turbine shaft.
6. The method of claim 1 additionally comprising the steps of:
connecting a stabilization member to the combustion chamber case; and
supporting said extended bearing nut tool on said stabilization member.
7. The method of claim 1 additionally comprising the steps of:
connecting a stabilization member to the combustion chamber case; and
supporting said extended high pressure turbine shaft stretching tool on said stabilization member.
8. The method of claim 1 additionally comprising the step of:
using a datum member having an arcuate portion to engage the aft end of said high pressure turbine shaft to measure distances from said datum member.