Engine structure assembly procedure
AssigneePratt & Whitney Canada Corp.
InventorsEugene GEKHT, Patrice REMY, Danny MILLS
Life of this patent
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Abstract
A method for centering an engine structure such as a bearing housing is provided which may be used for example, during assembly of a mid turbine frame or other engine case structure. The method according to one embodiment may include machining spokes with an outer case of the mid turbine frame in situ to eliminate stack-up and then applying the retaining device to retain the spokes with respect to the outer case, thereby assuring the co-axial relationship between the outer case and the bearing housing supported within the mid turbine frame.
Claims19
A method for making an assembly of a gas turbine engine structure, the assembly including at least co-axially positioned annular outer and inner cases interconnected by a plurality of circumferentially spaced load transfer members extending radially between the outer and inner cases, the method comprising:
- (1) substantially forming the assembly of the gas turbine engine structure on the fixture by positioning the outer case and the inner case co-axially with each other on a fixture and affixing a radially-inner end of each of the load transfer members to the inner case while letting a radially-outer end portion of each of the load transfer members extend radially through one of a plurality circumferentially spaced openings defined in the outer case;
- (2) creating a plurality of commonly machined surfaces each provided by a machined end surface of one of the load transfer members flush with and surrounded by a machined surface of the outer case, by temporarily securing the substantially formed assembly on the fixture and machining the radially-outer end portion of the respective load transfer members exposed through the respective openings of the outer case and machining an area of the outer case surrounding each of the radially-outer ends;
- and then
- (3) securing the co-axial position of the outer and inner cases before the assembly is removed from the fixture by attaching a retaining device to the outer case to retain the respective commonly machined surfaces in place.
A method for centering a bearing housing during a mid-turbine frame (MTF) assembly procedure, the method comprising:
- (1) forming a substantial MTF assembly on the fixture by positioning at least an outer case, an inner case, a plurality of radial spokes and the bearing housing on a fixture, attaching the bearing housing to and supporting the bearing housing in the inner case, affixing a radially-inner end of each of the radial spokes to the inner case while letting a radially-outer end portion of each of the spokes extend radially through one of a plurality circumferentially spaced openings defined in the outer case to expose an outer end of the radially-outer end portion through the respective openings, and positioning the outer case co-axially with the bearing housing;
- (2) creating a plurality of commonly machined surfaces each formed with a machined end surface of one of the radial spokes flush with and surrounded by a machined surface of the outer case by temporarily securing the substantial MTF assembly on the fixture and machining the radially-outer end of the respective radial spokes exposed through the respective openings of the outer case and machining an area of the outer case surrounding each of the radially-outer ends;
- and
- (3) securing the co-axial position of the outer case and the bearing housing to form the MTF for installation in a gas turbine engine by attaching a retaining device to the outer case to retain the respective commonly machined surfaces in place when the substantial MTF assembly is on the fixture.
Dependencies are inferred from the claim text.