GAS TURBINE ENGINE AUXILIARY COMPONENT MOUNT

Abstract

A method of installing a bracket to an engine casing of a gas turbine engine includes attaching a first mount segment of a first bracket to an auxiliary component and attaching a second mount segment of the first bracket to the engine casing. In one exemplary embodiment, the method can include attaching a second bracket to the auxiliary component on an opposite side of the auxiliary component from the first bracket.

Description

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of U.S. patent application Ser. No. 11/291,348, filed Dec. 1, 2005.

BACKGROUND

This disclosure relates to a mounting system, and more particularly to an energy absorbing mount system for a gas turbine engine auxiliary component.

Gas turbine aircraft engines utilize a turbine fan to draw ambient air into the engine for compression and combustion by the engine. The turbine fan is shrouded by an engine casing. Typically, a variety of auxiliary components such as engine oil tanks, gearboxes, valves, control systems for regulating the engine's operations, and other components are mounted to the engine casing. Various mounting systems mount the auxiliary components to the engine casing.

Conventional mounting systems typically include a plurality of rigid bracket members that are attached between the auxiliary component and the engine casing by a series of shear pins. Such conventional mounting systems may also include isolators that damp the transmission of engine vibratory loads to the auxiliary components during normal loading and operating conditions.

Conventional mounting systems may become subjected to a high degree of shock loading not experienced during normal engine operating conditions. For example, a high shock load may result from a fan-blade out event. A fan-blade out event occurs when a fan-blade breaks off of an engine rotor body as a result of impact with a foreign object. A fan-blade out event results in an imbalance in the engine rotor body which may also cause outward deflection and a rotor body shaft imbalance.

SUMMARY

A method of installing a bracket to an engine casing of a gas turbine engine includes attaching a first mount segment of a first bracket to an auxiliary component and attaching a second mount segment of the first bracket to the engine casing. In one exemplary embodiment, the method can include attaching a second bracket to the auxiliary component on an opposite side of the auxiliary component from the first bracket.

The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a gas turbine engine assembly having an auxiliary component for mounting on the engine's external casing;

FIG. 2 is a top view of a portion of a gas turbine engine assembly having an auxiliary component mounted to the engine casing with a mount system according to the present invention;

FIG. 3 is a side view of the assembly illustrated in FIG. 2;

FIG. 4 is a perspective view of a top bracket position with respect to an auxiliary component and an engine casing;

FIG. 5 is a bottom view of a portion of a gas turbine engine having an auxiliary component mounted to the engine casing with the mount system according to the present invention;

FIG. 6 is a perspective view of a side bracket according to the present invention;

FIG. 7 is a perspective view of the side bracket of the present invention after experiencing a high shock loading event.

DETAILED DESCRIPTION

Referring to FIG. 1, a gas turbine engine 10 generally includes a fan section 12, a compressor section 14, a combustion section 16 and a turbine section 18. The compressor section 14 and the turbine section 18 each contain one or more stages of a compressor and a turbine (not shown) which rotate about an engine longitudinal axis 20. The components of the gas turbine engine 10 are circumscribed by an essentially cylindrical engine casing 22. The engine casing 22 serves as a main structural support for the gas turbine engine 10. The engine casing 22 is usually constructed of individual case sections, such as case sections 24 and 26, which are joined together at bolted flanges such as engine case flange 30.

An auxiliary component 32 is mounted to the engine casing 22 by a mount system 40 along an auxiliary component axis A which is generally transverse to the engine longitudinal axis 20. The auxiliary component 32 may include any component known in the art that requires mounting to the engine casing 22, including but not limited to an oil tank, a gearbox, valves and electronic control systems for regulating the operations of the gas turbine engine 10, and may be mounted in any orientation.

Referring to FIG. 2, a three-point mount system 40 includes side brackets 42, 44 and a top bracket 46. It should be understood that fewer or additional brackets may be utilized to mount an auxiliary component 32 within the contemplation of this invention. One side bracket 42, 44 is positioned on each side of the auxiliary component 32, forward and aft thereof relative to the gas turbine engine longitudinal axis 20. The side brackets 42, 44 are preferably positioned on each side of the auxiliary component 32 center of gravity. It should be understood that the position of the side brackets 42, 44 may vary depending upon the size and shape of the auxiliary component 32. Generally, the side brackets 42, 44 are positioned nearest to the average location of the weight of the auxiliary component 32 as possible without interfering with design functionality. By positioning the side brackets 42, 44 near the average location of the weight of the auxiliary component, the side brackets 42, 44 provide a rigid attachment of the auxiliary component 32 to the engine casing 22 during normal engine operation to generally reduce vibration therefrom.

Referring to FIG. 3, the top bracket 46 is located axially forward of the side brackets 42, 44 along the axis A of the auxiliary component 32. The top bracket 46 is positioned generally parallel relative to the engine longitudinal axis 20 of the gas turbine engine 10 near a top end segment 51 of the auxiliary component 32. It should be understood that other orientation and bracket combinations will also be usable with the present invention.

Referring to FIG. 4, the top bracket 46 includes a set of arms 57, 59 and a neck portion 61. The set of arms 57, 59 are each attached to a separate engine case flange 30. The set of arms 57, 59 of the top bracket 46 engage the auxiliary component 32 through a multitude of fasteners F to provide a relatively flexible cradle between the auxiliary component 32 and the engine casing 22. That is, the side brackets 42, 44 are the primary supports for the auxiliary component 32 while the top bracket 46 generally stabilizes the auxiliary component therebetween.

The bracket components, including the side brackets 42, 44 and the top bracket 46, are preferably constructed of a sheet metal material. The brackets can be made entirely from AMS5599, Inconel 625 (nickel-alloy). This material is well suited for the present invention, because of its relative stiffness while simultaneously having a high plasticity and good fatigue properties. It should be understood that other materials and combinations thereof may be utilized to construct the brackets of the mount system of the present invention.

Referring to FIG. 5, the auxiliary component 32 is here mounted to the engine casing 22 such that the auxiliary component axis A (extending into the page) is transverse to the engine longitudinal axis 20 of the engine casing 22. It should be understood that various mounting arrangements are possible for the auxiliary components, and may depend on design specific parameters. The side brackets 42, 44 are aligned generally along the engine longitudinal axis 20 of the engine casing 22 and on each side of the auxiliary component axis A.

Each side bracket 42, 44 defines a first mount segment 50 and a second mount segment 52. The first and second mount segments 50, 52 are planar members which are generally parallel to one another. The first mount segment 50 attaches to the auxiliary component 32 and the second mount segment 52 attaches to the engine casing 22. Preferably, the mount segments 50, 52 are fastened to the auxiliary component 32 and the engine casing 22, respectively through a plurality of apertures formed in the mount segments 50, 52 (also illustrated in FIG. 6).

The side brackets 42, 44 are manufactured of three layers, although it should be understood that any number of layers may be used to form the mount segments 50, 52. The layers are preferably riveted together at rivets R (FIG. 6) to maintain the structural integrity of the mount segments 50, 52; however, other attachments including welding may also be utilized to sandwich the layers of the brackets 42, 44. The mount segments 50, 52 may include weight reducing openings 53 to still further reduce the overall weight of the side brackets 42, 44. The construction of the side brackets 42, 44 preferably requires no welding, brazing or the like. The side brackets 42, 44 are assembled from three pieces of sheet metal. Separation of the individual segments of the side brackets 42, 44 as hereinabove described is for purposes of description only.

Each side bracket 42, 44 includes a deformable member 60 sandwiched between a first and a second retainer member 62, 64. The deformable member 60 defines a planar segment 74 which extends transversely to the mount segments 50, 52. The deformable member 60 is sandwiched between a first retainer member 62 and a second retainer member 64. The retainer members 62 and 64 include at least partially non-planar segments 72 between the mount segments 50, 52. The non-planar segments 72 flank but are separated from the planar segment 74 of the deformable member 60 between the planar mount segments 50, 52. That is, the retainer members 62, 64 sandwich the deformable member 60 therebetween to provide a laminated side bracket 42, 44 design.

The planar segment 74 of the deformable member 60 defines a series of openings 70 generally transverse to the mount segments 50, 52. The size and quantity of the openings 70 is determined by application specific parameters including the shear strength and the load strength of the material used to fabricate the deformable member 60 and the magnitude of the shock loads expected to be experienced by the deformable member 60. It should be understood that the deformable member 60 may be designed with a single opening or without any openings 70 by utilizing a more brittle material as a substitute for the nickel-alloy sheet metal material preferably used to fabricate the deformable member 60. In one example, titanium is substituted as the material for the deformable member 60. The deformable member 60 is designed to reach ultimate strain at a predetermined load that is expected to be experienced during a particular high shock load such as during a fan-blade out event.

The first retainer member 62 and the second retainer member 64 are disposed on each side of the deformable member 60 to sandwich the deformable member 60 therebetween. The retainer members 62, 64 each include the non-planar segment 72 adjacent the planar segment 74 of the deformable member 60. Preferably, the non-planar segments 72 are pre-formed sections that to include an arcuate bend.

During normal engine operation, the side brackets 42, 44 and the top bracket 46 are sufficiently stiff to rigidly support the auxiliary component 32. The retainer members 62, 64 and the deformable member 60 of the side bracket 42, 44 provide the necessary rigidity to support the auxiliary component 32 relative to the engine casing 22.

Referring to FIG. 7, the side bracket 42, 44 is illustrated after being subjected to a fan-blade out event. That is, the openings 70 provide a predefined failure area. Relatively severe engine rotor imbalance occurs due to the fan-blade out event such that the deformable member 60 may tear, shear, buckle, fuse or otherwise deform in tension along the openings 70. The plastic deformation of the deformable member 60 absorbs a majority of the high shock load. The balance of the shock loads are absorbed by the retainer members 62, 64 in which the non-planar segments 72 of the retainer members 62, 64 extend (illustrated schematically by arrow B) and collapse toward or bulge away from each other to provide a further load absorption path. That is, the combination of the deformable member 60 failure and extension of the non-planar segments 72 of the retainer members 62, 64 absorb the high shock load by essentially extending the time period of the high shock load event. The retainer members 62, 64 also retain the auxiliary component 32 to the engine casing 22 subsequent to the fan-blade out event such that the auxiliary component 32 does not break completely free. In this way, the mount system 40 may be sacrificed while the integrity of the auxiliary component 32 is maintained.

The foregoing shall be interpreted as illustrative and not in a limiting sense. A worker of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Claims

1. A method of installing a bracket to an engine casing of a gas turbine engine, comprising the steps of:

attaching a first mount segment of a first bracket to an auxiliary component; and

attaching a second mount segment of the first bracket to the engine casing.

2. The method as recited in claim 1, comprising the step of:

attaching a second bracket to the auxiliary component on an opposite side of the auxiliary component from the first bracket.

3. The method as recited in claim 2, wherein the second bracket is also attached to the engine casing.

4. The method as recited in claim 2, wherein the first bracket and the second bracket are positioned on each side of a center of gravity of the auxiliary component.

5. The method as recited in claim 2, wherein the first bracket and the second bracket are aligned along an engine longitudinal axis of the engine casing on each side of an axis of the auxiliary component.

6. The method as recited in claim 1, comprising the step of:

installing a second bracket to the auxiliary component at an axially forward position of the auxiliary component from the first bracket.

7. The method as recited in claim 1, wherein an axis of the auxiliary component is transverse to an engine longitudinal axis of the engine casing.

8. The method as recited in claim 1, wherein the first bracket includes a deformable member sandwiched between the first mount segment and the second mount segment.

9. The method as recited in claim 1, wherein the first bracket is positioned at an average location of a weight of the auxiliary component.

10. The method as recited in claim 1, comprising the step of:

subsequent to the steps of attaching the first mount segment and attaching the second mount segment, absorbing a high shock load with a portion of the first bracket to retain the auxiliary component to the engine casing.