Seal assembly

A sprung seal assembly includes a flexible sprung seal having a center section disposed between opposing curved and cantilevered first and second end sections. First and second free edges of the first and second end sections respectively are trapped within a retainer. First and second sliding lugs attached to the first and second free edges respectively are slidably disposed in first and second channels respectively. The first and second free edges are trapped in the retainer by the first and second sliding lugs disposed in the first and second channels between a mounting surface and the retainer attached to the mounting surface. The center section may have a wear strip. The sprung seal assembly may be disposed between a relatively fixed sidewall and a relatively movable flap of a nozzle assembly. The retainer is mounted to the flap and the center section is in sealing engagement with a sealing surface of the sidewall.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to seals between adjacent relatively moveable members and, more particularly, to a sprung seal usable in a gas turbine engine exhaust nozzle.

2. Description of Related Art

Variable area and vectoring exhaust nozzles of aircraft gas turbine engines for aircraft typically employ two dimensional (2D) nozzles having relatively stationary sidewalls movable flaps. The sidewalls and flaps define, at least in part, boundaries of a hot exhaust flowpath in the nozzle and employ seals between them to contain hot pressurized exhaust gases within the exhaust flowpath and prevent them from leaking out of the nozzle. During the nozzle's operation, the flaps are moved, typically rotated about an axis, and the flaps slide relative to the sidewalls. Space between the moveable flaps and the stationary sidewalls provides a leakage path for relatively high pressure gases in the exhaust flowpath. A major concern in the design of such exhaust systems, therefore, is the control of leakage through a space or gap between the two relatively slidable members. Thus, seals are provided to reduce or substantially eliminate leakage between the members or flaps and the sidewalls.

Exemplary types of exhaust seals that have been used in the past are elastic leaf seals and hinge leaf seals. Elastic leaf seals consist of a generally “U”, “S”, or otherwise shaped member which is fastened on one side to one of the members to be sealed and is in rubbing contact on its other side to the other member. This seal may be spring loaded so that as the two members move apart, it maintains contact therebetween. The seals are designed to be strong enough to withstand the relatively high pressure of the exhaust flow gases and to be flexible enough to expand and contract with variations in the gap. Hinge leaf seals generally include two flat sheets which pivot from a common hinge point. One of the sheets is attached to one of the members to be sealed and the other sheet is in rubbing contact with the other member.

New modern nozzle designs call for sealing between relatively movable members which undergo large relative movement and at least one of the members may have a contoured sealing surface. Thus, it is highly desirable to have an effective seal for sealing between relatively movable members which undergo large relative movement, one of which has a contoured sealing surface.

SUMMARY OF THE INVENTION

A sprung seal assembly includes a flexible sprung seal having a center section disposed between opposing curved cantilevered first and second end sections. First and second free edges of the first and second end sections respectively are trapped within a retainer. An exemplary embodiment of the sprung seal assembly includes first and second sliding lugs attached to the first and second free edges respectively. The first and second sliding lugs are slidably disposed in first and second channels respectively in the retainer. The retainer is attached to a mounting surface thus trapping the first and second free edges within the retainer. The first and second free edges are trapped between the mounting surface and the retainer by the first and second sliding lugs disposed in the first and second channels. The first and second sliding lugs may be cylindrical. The center section may have a wear strip which may be a center plate.

The sprung seal assembly may be disposed between first and second relatively movable members of a sealable assembly. The retainer is mounted to one of the first and second relatively movable members and the center section is in sealing engagement with another of the first and second relatively movable members. The sprung seal assembly may also be disposed between a relatively fixed sidewall and a relatively movable flap of an aircraft gas turbine engine exhaust nozzle assembly. The retainer is mounted to the flap and the center section is in sealing engagement with the sidewall.

DETAILED DESCRIPTION OF THE INVENTION

Illustrated inFIG. 1is a sealable assembly10including a sprung seal assembly20disposed between first and second relatively movable members12,14. Such a sealable assembly may be used in the exhaust nozzle of an aircraft gas turbine engine as described below. The first and second members12,14are subject to movement in mutually perpendicular first and second directions15,16. The first and second members12,14may both be movable or one may be fixed. As an example the sprung seal assembly20may be used in an aircraft engine exhaust nozzle between two movable flaps or a movable sidewall and a movable flap. The sprung seal assembly20including a flexible sprung seal22having a center section24disposed between opposing curved cantilevered first and second end sections26,28. The flexible sprung seal22is illustrated as made from a strip of a flexible or springy material such as a metal capable of withstanding high temperature as may be found in an aircraft engine exhaust nozzle.

Spaced apart first and second free edges30,32of the first and second end sections26,28respectively are trapped within a retainer36by first and second sliding lugs40,42attached to the free edges. The first and second sliding lugs40,42are slidably disposed and trapped in spaced apart first and second channels50,52respectively in the retainer36. The first and second sliding lugs40,42together with the first and second free edges30,32are trapped between the retainer36and a mounting surface60which is substantially parallel to the center section24and to which the retainer36is attached.

The retainer36is mounted to one of the first and second relatively movable members12,14along the mounting surface60and the center section24is in sealing engagement with a sealing surface19of another of the first and second relatively movable members12,14. The sealing surface19is parallel to the mounting surface60. The retainer36in the exemplary embodiment illustrated herein is mounted to the first member12. The center section24in the exemplary embodiment illustrated herein is in sealing engagement with the sealing surface19of the second member14. The center section24may have a wear strip66illustrated herein as a center plate68. The mounting surface60is illustrated herein as a surface on a mounting bracket61attached to the first member12.

InFIG. 1, the first and second sliding lugs40,42are illustrated as first and second cylindrical lugs44,46welded or otherwise attached to the first and second free edges30,32of the first and second end sections26,28respectively inFIG. 1. First and second alternative seals in the form of flexible sprung concentric seals23are illustrated inFIGS. 2 and 3, respectively. The alternative flexible sprung concentric seals23have inner and outer flexible strips70,72made of a flexible material such as a metal capable of withstanding high temperature as may be found in an exhaust nozzle.

The inner and outer flexible strips70,72are shaped like the flexible sprung seal22illustrated inFIG. 1. Each of the inner and outer flexible strips70,72has a center sections (not illustrated inFIGS. 2 and 3) disposed between opposing curved cantilevered first and second end sections (not illustrated inFIGS. 2 and 3). Inner and outer free edges130,132of the end sections respectively are trapped within a retainer36by inner and outer sliding lugs140,142attached to the inner and outer free edges130,132. Each of the inner and outer flexible strips70,72has first and second sets of inner and outer sliding lugs140,142attached to first and second sets of the inner and outer free edges130,132and disposed in the first and second channels50,52respectively in the retainer36that is illustrated inFIG. 1. The first and second sliding lugs40,42illustrated inFIG. 2are about 90 degree bends76in the inner and outer free edges130,132. The first and second sliding lugs40,42illustrated inFIG. 3are about 300 degree bends78in the inner and outer free edges130,132.

Illustrated inFIGS. 4-6is a portion of an aircraft gas turbine engine exhaust nozzle assembly8including a relatively fixed sidewall11and a relatively movable flap13. The fixed sidewall11is also illustrative of a fixed liner of a fixed sidewall and the movable flap13is also illustrative of a movable liner as may found in an aircraft gas turbine engine exhaust nozzle. The fixed sidewall11may be curved or contoured having simple or complex contours21or shapes. The fixed sidewall11and the movable flap13define, at least in part, boundaries of a hot exhaust flowpath25in the nozzle exhaust nozzle assembly8and employs a sprung seal assembly20between them to contain hot pressurized exhaust gases within the exhaust flowpath and prevent them from leaking out of the nozzle assembly. During the nozzle assembly's operation, flaps are moved, typically rotated about an axis, and flaps slide relative to the sidewalls or to other movable flaps. Space between the moveable flaps and the stationary sidewalls provides a leakage path for relatively high pressure gases in the exhaust flowpath which is sealed by the sprung seal assembly20.

The sprung seal assembly20similar to the one illustrated inFIG. 1is disposed between the sidewall11and the flap13. A flexible sprung seal22of sprung seal assembly20, illustrated in cross-section inFIG. 1, includes a center section24disposed between opposing curved cantilevered first and second end sections26,28. First and second free edges30,32of the first and second end sections26,28respectively are trapped within a retainer36. The retainer36is mounted to the flap13and the center section24is in sealing engagement with a sealing surface19of the sidewall11. The flexible sprung seal22may be curved or have simple or complex contours21or shapes to better match those of and seal against the fixed sidewall11.

First and second sliding lugs40,42are attached to the first and second free edges30,32respectively. The first and second sliding lugs40,42are slidably disposed in first and second channels50,52respectively in the retainer36. The retainer36is attached to the flap13on a mounting surface60of the flap13. The first and second free edges30,32are trapped within the retainer36by the first and second sliding lugs40,42disposed in the first and second channels50,52respectively between the retainer36and the mounting surface60. The retainer36is mounted on a lengthwise extending L bracket90which in turn is mounted on a lengthwise extending C bracket92which is attached to the flap13.

InFIGS. 4-6, the first and second sliding lugs40,42are illustrated as first and second cylindrical lugs44,46welded or otherwise attached to the first and second free edges30,32of the first and second end sections26,28respectively inFIG. 1. The first and second alternative flexible sprung concentric seals23having the inner and outer free edges130,132illustrated inFIGS. 2 and 3respectively may also be used in the embodiment illustrated inFIGS. 4-6. The first and second sliding lugs40,42may be the 90 degree bends76or the 300 degree bends78in the inner and outer free edges130,132.

While there have been described herein what are considered to be preferred and exemplary embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein and, it is therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention. Accordingly, what is desired to be secured by Letters Patent of the United States is the invention as defined and differentiated in the following claims.