Patent Application
20120177495
The present disclosure relates to gas turbine engines, and in particular, to a heat shield therefor.
In a gas turbine engine, rotor cavities are often separated by full hoop shells. Significant temperature difference may occur between steady state and transient operational conditions in adjacent rotor cavities. Where components which form the adjacent rotor cavities are mated by a radial interference fit, such significant temperature differences may complicate the initial radial interference fit requirements for assembly and disassembly.
A rotor disk assembly for a gas turbine engine according to an exemplary aspect of the present disclosure includes a rotor disk defined about an axis of rotation. The rotor disk has a circumferentially intermittent slot structure that extends radially outward relative to the axis of rotation. A heat shield has a multiple of radial tabs which extend radially inward relative to the axis of rotation. The multiple of radial tabs are engageable with the circumferentially intermittent slot structure to provide axial retention of the cover plate to the rotor disk.
A gas turbine engine according to an exemplary aspect of the present disclosure includes a rotor disk defined about an axis of rotation. The rotor disk has a circumferentially intermittent slot structure and a flange that extends radially outward from a cylindrical extension relative to the axis of rotation. A front cover plate defined about the axis of rotation, the front cover plate having a stop which extends radially inward from a cylindrical extension of the front cover plate relative to the axis of rotation. The front cover plate is located adjacent to the rotor disk such that the stop is adjacent to the flange. A heat shield is defined about the axis of rotation, the heat shield has a multiple of radial tabs which extend radially inward relative to the axis of rotation. The heat shield is located adjacent to the front cover plate such that the multiple of radial tabs engage with the circumferentially intermittent slot structure to provide axial retention of the front cover plate to the rotor disk.
A method to assemble a rotor disk assembly according to an exemplary aspect of the present disclosure includes locating a cover plate adjacent to a rotor disk along an axis of rotation. Axially locating a heat shield having a multiple of radial tabs which extend radially inward relative to the axis of rotation, the multiple of radial tabs axially aligned with openings defined by a circumferentially intermittent slot structure on the rotor disk. Rotating the heat shield to radially align the multiple of radial tabs with the circumferentially intermittent slot structure to axially retain the cover plate to the rotor disk.
Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiment. The drawings that accompany the detailed description can be briefly described as follows:
Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines.
The engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted upon a multiple of bearing systems for rotation about the engine central longitudinal axis A relative to an engine stationary structure. The low speed spool 30 generally includes an inner shaft 34 that interconnects a fan 35, a low pressure compressor 36 and a low pressure turbine 38. The inner shaft 34 may drive the fan 35 either directly or through a geared architecture 40 to drive the fan 35 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 42 that interconnects a high pressure compressor 44 and high pressure turbine 46. A combustor 48 is arranged between the high pressure compressor 44 and the high pressure turbine 46.
Core airflow is compressed by the low pressure compressor 36 then the high pressure compressor 44, mixed with the fuel in the combustor 48 then expanded over the high pressure turbine 46 and low pressure turbine 38. The turbines 38, 46 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion.
With reference to
The components may be assembled to the outer shaft 42 from fore-to-aft (or aft-to-fore, depending upon configuration) and then compressed through installation of a locking element (not shown) to hold the stack in a longitudinal precompressed state to define the high speed spool 32. The longitudinal precompressed state maintains axial engagement between the components such that the axial preload maintains the high pressure turbine 46 as a single rotary unit. It should be understood that other configurations such as an array of circumferentially-spaced tie rods extending through web portions of the rotor disks, sleeve like spacers or other interference and/or keying arrangements may alternatively or additionally be utilized to provide the tie shaft arrangement.
Each of the rotor disks 56, 62 are defined about the axis of rotation A to support a respective plurality of turbine blades 66, 68 circumferentially disposed around a periphery thereof. The plurality of blades 66, 68 define a portion of a stage downstream of a respective turbine vane structure 70, 72 within the high pressure turbine 46. The cover plates 54, 58, 60, 64 operate as air seals for airflow into the respective rotor disks 56, 62. The cover plates 54, 58, 60, 64 also operate to segregate air in compartments through engagement with fixed structure such as the turbine vane structure 70, 72.
With reference to
The mating components between the high pressure turbine 46 and the high pressure compressor 44 in the disclosed non-limiting embodiment are the first turbine rotor disk 56 and the high pressure compressor rear hub 86. Axial retention of the first front cover plate 54 is thereby provided by the heat shield 52 and the first turbine rotor disk 56.
With reference to
A flange 90 extends radially outward from a cylindrical extension 56C of the first turbine rotor disk 56 to be adjacent to a cover plate stop 92 which extends radially inward from a cylindrical extension 54C of the first front cover plate 54. A circumferentially intermittent slot structure 94 extends radially outward from the cylindrical extension 56C of the first turbine rotor disk 56 just upstream, i.e., axially forward, of the flange 90 to receive the radial tabs 88. Although a particular circumferentially intermittent slot structure 94 which is defined by circumferentially intermittent pairs of axially separated and radially extended tabs is illustrated in the disclosed non-limiting embodiment, it should be understood that various types of lugs may alternatively be utilized.
In a method of assembly, the first front cover plate 54 is located adjacent to the first turbine rotor disk 56 such that the cover plate stop 92 is adjacent to the flange 90 and may be at least partially axially retained by the radial tabs 88. A step surface 52S in the cylindrical extension 52C (
The heat shield 52 is located axially adjacent to the first front cover plate 54 such that the radial tabs 88 pass through openings formed by the circumferentially intermittent slot structure 94. The heat shield 52 (also shown in
An annular spacer 98 (
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.
Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention.
The foregoing description is exemplary rather than defined by the limitations within. Various non-limiting embodiments are disclosed herein, however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.
