Rotary kinetic fluid motors or pumps – Including thermal expansion joint – Radially sliding
Reexamination Certificate
2001-04-06
2003-04-15
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Including thermal expansion joint
Radially sliding
C415S209400
Reexamination Certificate
active
06547518
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to gas turbine engine frames and, in particular, to supporting gas turbine engine turbine frames from radially outer casings.
2. Discussion of the Background Art
Gas turbine engines and, in particular, aircraft gas turbine engines employ two or more structural assemblies, referred to and known as frames, to support and accurately position the engine rotor within the stator. Each frame includes an inner ring and an outer ring connected by a number of radial struts extending therebetween and contoured for minimum interference with the engine flow. The outer ring is connected to an engine inner casing by a radially outer conical support arm and a radially inner conical support arm support is used for supporting a bearing assembly. The radially inner conical support arm support is typically connected and used to support a sump of the bearing assembly. In some engine designs, the inner casing is mounted within and to an outer engine casing by links. Hollow passage are often provided through the strut to pass service lines such as sump service tubes and also sometimes to pass cooling air across hot working gas flow contained in a turbine flowpath between the inner and outer rings and the radial struts.
The radially outer and inner conical support arms are exposed to high temperatures, transmit loads, and are continuous hoops subject to hoop stress. The hoop stress is due to substantial operating temperature differentials between the frame and the bearing and between the frame and the inner casing. It is desirable to have a design for the radially outer and inner conical support arms of the frame and turbine assembly that reduces or eliminates these hoop stresses in the support arms.
SUMMARY OF THE INVENTION
In the exemplary embodiment of the present invention as illustrated herein, a gas turbine frame has inner and outer annular bands, respectively, joined together by generally radially extending struts therebetween. A radially outer conical support arm extends radially outwardly from the outer band and a radially inner conical support arm extends radially inwardly from the inner band. Circumferentially spaced apart inner and outer openings are disposed in the inner and outer conical support arms, respectively. Each of the struts has at least one radially extending hollow passage which extends through the inner and outer bands. The frame is a single piece integral casting. The inner and outer conical support arms have an equal number of the inner and outer circumferentially spaced apart openings. The inner circumferentially spaced apart openings are equi-angularly spaced apart and the outer circumferentially spaced apart openings are equi-angularly spaced apart. Each pair of the inner and outer circumferentially spaced apart openings are linearly aligned with the hollow passage of a corresponding one of the struts.
In one particular embodiment of the invention, each opening has a substantially rectangular platform shape with rounded forward and aft ends and, in another embodiment, each opening has a substantially triangular platform shape with filleted corners.
The frame of the present invention provides a structural connection between the relatively cool engine casing and the inner sump of the bearing across a relatively hot flowpath while avoiding destructive levels of thermal hoop stress which occur in prior art designs. The invention also can improve the castability of the one piece integrally cast frame of the invention by providing openings into narrow cavities between the bands and the support arms. This feature eases production of the investment casting. The invention may also provide thermal flexibility which also improves castability by reducing the propensity for hot tearing of a casting alloy during solidification. The cutouts or openings also provide access to strut ends for inserting sump service tubing.
REFERENCES:
patent: 4571936 (1986-02-01), Nash et al.
patent: 4907946 (1990-03-01), Ciokajlo et al.
patent: 4989406 (1991-02-01), Vdoviak et al.
patent: 5165850 (1992-11-01), Humke et al.
patent: 5249921 (1993-10-01), Stueber et al.
patent: 5272869 (1993-12-01), Dawson et al.
patent: 5597286 (1997-01-01), Dawson et al.
patent: 5634767 (1997-06-01), Dawson
Czachor Robert Paul
Strang Steven Andrew
General Electric Company
Herkamp Nathan D.
McCoy Kimya N
Rosen Steven J.
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