Patent Application
20090060746
The present invention generally relates to turbine engine rotor assemblies and more particularly to a blade retaining clip that locks a turbine blade to a rotor disk or hub that carries the blade.
Turbine engines are used as the primary power source for many types of aircraft. The engines are also auxiliary power sources that drive air compressors, hydraulic pumps, and industrial gas turbine (IGT) power generation. Further, the power from turbine engines is used for stationary power supplies such as backup electrical generators for hospitals and the like.
Most turbine engines generally follow the same basic power generation procedure. Compressed air generated by axial and/or radial compressors is mixed with fuel and burned, and the expanding hot combustion gases are directed against stationary turbine vanes in the engine. The vanes turn the high velocity gas flow partially sideways to impinge on a plurality of turbine blades mounted on a rotatable turbine disk. The force of the impinging gas causes the turbine disk to spin at high speed. Jet propulsion engines use the power created by the rotating turbine disk to draw more air into the engine, and the high velocity combustion gas is passed out of the gas turbine aft end to create forward thrust. Other engines use this power to turn one or more propellers, fans, electrical generators, or other devices.
In a typical turbine engine, the rotating turbine disk includes a means for securing the plurality of blades to the disk. In general, a plurality of slots are formed about the periphery of the rotating turbine disk into which a root portion of a single turbine blade is inserted. Currently, turbine blades are often secured within the rotating turbine disk slots using retaining clips that are fabricated using a stamping process. One particular design for the blade retaining clip includes a substantially linear shank portion having an upwardly curved profile between opposing end portions. A first end portion of the blade retaining clip is pre-bent during fabrication. The clip is positioned within the turbine disk slot to hold the turbine blade therein. After positioning, the turbine blade is inserted into the disk and the second end portion of the clip is bent during final rotor assembly, thereby securing the turbine blade within the turbine disk slot. During operation of the turbine disk, a force is created upon the linear shank portion of the blade retaining clip, forcing it in a downward direction relative to the upward curvature of the shank profile and forcing a corresponding movement of the first and second end portions inward toward the rotor, potentially causing large axial loads where the two end portions engage the rotor and associated, undesirable operating stresses in the curved regions of the two end portions.
It should thus be appreciated from the above that it would be desirable to provide a blade retaining clip for the securement of a blade component within a rotating disk that is configured to prevent undesirable operating stresses in the end portions of the blade retaining clip. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.
The present invention provides a blade retaining clip for the securement of a blade component within a rotating disk that is configured to prevent the generation of operating stresses at the end portions of the blade retaining clip, resulting in possible failure of the blade retaining clip.
In one embodiment, and by way of example only, provided is a blade retaining clip for axially securing a root portion of a blade within an axially extending slot of a rotating disk. The blade retaining clip comprising: an elongate shank portion having a length at least equal to the axially extending slot of the rotating disk; and a first end portion and a second end portion, integrally formed at opposed ends of the elongate shank portion, the first end portion and the second end portion extending upwardly from the elongate shank portion and configured to secure the root portion of the blade within the axially extending slot of the rotating disk. The elongate shank portion having an axial downwardly curved profile.
In yet another embodiment, and by way of example only, provided is a blade retaining clip for axially securing a root portion of a blade within an axially extending slot of a rotating disk. The blade retaining clip comprising: an elongate shank having a substantially rod-like shape and a length at least equal to the axially extending slot of the rotating disk; and a first end portion and a second end portion, integrally formed at opposed ends of the elongate shank, the first end portion and the second end portion extending upwardly from the elongate shank portion and configured to include a plurality of retention stops to secure the blade within the axially extending slot of the rotating disk. The elongate shank portion having an axial downwardly curved profile.
In still another embodiment, and by way of example only, provided is a blade assembly for a turbine engine comprising: a rotating disk including a plurality of axially extending slots formed about a periphery of the rotating disk; an annular array of blades extending radially outwardly from the rotating disk, each of the blades including a root portion and an airfoil portion, the root portion of each blade positioned in one of the plurality of axially extending slots; and a plurality of blade retaining clips, one of the plurality of blade retaining clips positioned within each of the plurality of axially extending slots and providing radial retention of the each of the blades of the annular array of blades. Each of the plurality of blade retaining clips comprising: an elongate shank having a substantially rod-like shape, a length at least equal to an axially extending slot of the rotating disk, and an axial downwardly curved profile; and a first end portion and a second end portion, integrally formed at opposed ends of the elongate shank, the first end portion and the second end portion extending upwardly from the elongate shank portion and configured to secure a blade of the annular array of blades within an axially extending slot of the plurality of axially extending slots of the rotating disk.
Other independent features and advantages of the preferred methods will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.
Before proceeding with a detailed description, it is to be appreciated that the described embodiment is not limited to use in conjunction with a particular type of turbine engine, or even for use in conjunction with a rotor assembly of a turbine engine. Thus, although the present embodiment is, for convenience of explanation, depicted and described as being implemented in a rotor assembly included within a turbine jet engine, it will be appreciated that it can be implemented in various other types of systems that include blade assemblies including a rotating disk and the need to secure blades to the rotating disk.
Referring now to
The compressor section 104 includes two compressor stages; an intermediate pressure compressor 120 and a high pressure compressor 122 interconnected by a rotary shaft 121 and a secondary cooling airflow system. The rotary shaft 121 interconnects the intermediate pressure compressor 120 and the high pressure compressor 122 in torque transmitting relationship. The intermediate pressure compressor 120 raises the pressure of the air directed into it from the fan 112, and directs the compressed air into the high pressure compressor 122. As best illustrated in
The high pressure compressor 122, in the depicted embodiment, includes a high pressure diffuser case 140 and a rotationally mounted high pressure impeller 144. The high pressure diffuser case 140 couples the intermediate pressure compressor 120 to the high pressure compressor 122 and directs exhausted air into the high pressure impeller 144. The high pressure impeller 144 has a plurality of vanes 146 extending there from that accelerate and compress the air. The high pressure impeller 144 compresses the air still further, and directs the high pressure air into the combustion section 106.
In the combustion section 106, which includes a combustor 124, the high pressure air is mixed with fuel and combusted. The combustor 124 receives the high pressure air from the compressor section 104 and mixes it with fuel to generate combusted air. The combusted air is then directed into the turbine section 108.
In this particular example, the turbine section 108 includes three turbines disposed in axial series flow, although it should be understood that any number of turbines may be included according to design specifics. More specifically,
For the purposes of this disclosure, the blade retaining clip disclosed herein may be used with numerous types of blade assemblies, including any of those described above. More particularly, the blade retaining clip disclosed herein may be used in conjunction with the previously described components: (i) the fan assembly 112; (ii) the intermediate pressure compressor 120 and the high pressure compressor 122, and more particularly the securing of the plurality of rotor blades 134 to the rotors 130; and (iii) the high pressure turbine 150, the intermediate pressure turbine 152, and the low pressure turbine 154, and more particularly the securing of the plurality of turbine blades 160 to the rotatable turbine disks 162.
Referring now to
The blade retaining clip 200 is preferably formed by well known sheet metal stamping techniques. As best illustrated in
Referring now to
The rotating disk 230 includes a plurality of axially extending slots 232 formed about a periphery of the rotating disk 230 and of corresponding cross-sectional configuration to receive the root portion 224 of the blade 220. The axial retention of each root portion 224 into a corresponding slot 232 is provided by the blade retaining clip 200. The axial dimension of each of the axially extending slots 232 is approximately equal to the length of the elongate shank portion 206 of the blade retaining clip 200. The blade retaining clip 200 is positioned within the slot 232 of the disk 230 prior to insertion of the blade 220, such that the end portion 204 that was not previously bent protrudes from one end of the slot 232. Next, the blade 220 is inserted into the disk 230, and once the blade root portion 224 is properly positioned, the unbent end portion 204 is bent in an upward direction as previously described, and toward the root portion 224 to form the retention stop 212, thus securing the blade 220 within the rotating disk 230.
The blade retaining clip 200 described herein thus provides an improved means for providing axial securement of a root portion 224 of a blade 220 in a retaining slot 232 of a rotating disk 230. The blade retaining clip 200 utilizes an elongate shank portion 206 including a downwardly curved profile to offset operational stresses exerted upon the end portions 202 and 204 of the blade retaining clip 200.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
