BACKGROUND

The present invention is related to gas turbine engines, and in particular to a system for positioning variable guide vanes.

Gas turbine engines rely on rotating and stationary components to effectively and efficiently control the flow of air through the engine. Rotating components include rotor blades employed in compressor and turbine sections for compressing air and extracting energy from air after combustion. Stationary components include vanes placed in the airflow to aid in directing airflow. By varying the position of the vanes (i.e., rotating them to vary the profile provided to the airflow), airflow characteristics can be optimized for various operating conditions.

One system for providing actuation of the vanes is a linear actuator connected to the plurality of variable guide vanes via a series of linkages and synchronizing rings. Splice brackets are used to bridge the halves of the synchronizing ring together. Excess deflections of the linkages and/or synchronizing rings will affect system's ability to control the position of the variable vanes accurately. Specifically, deflection of the synchronizing ring causes variation of the vane positions around the vane stage. Typically, adjustable composite bumpers mounted on the inner diameter of the synchronizing ring (along with high synchronizing ring stiffness) are used to limit the radial deflection of the synchronizing ring during normal engine operation conditions. However, under some engine conditions such as engine surge condition, much higher loads can cause excessive deflections of the synchronizing ring. These deflections can result in stresses exceeding the yield strength of the synchronizing ring and adjoining splice brackets. These deflections cannot be accommodated by typical composite bumper designs within the constrained space of some gas turbine engines.

SUMMARY

A bumper assembly includes a bracket and a pad. The pad is connected to the bracket by a first rivet.

A synchronizing ring assembly for a gas turbine engine includes a ring section and a bumper assembly. The bumper assembly is connected to a side surface of the ring section and extends axially adjacent an inner radial surface of the ring. The bumper assembly is disposed adjacent a gap at an end of the ring section. A gas turbine engine includes an engine case, a compressor and/or turbine section with a first stage of variable guide vanes, a synchronizing ring assembly, and a surge bumper assembly. The synchronizing ring assembly is disposed about the engine case and is connected to the first stage of variable guide vanes. The surge bumper assembly is connected to a first side surface of the synchronizing ring assembly. The surge bumper assembly extends axially adjacent an inner radial surface of the synchronizing ring assembly and is configured to contact the engine case during select engine operating conditions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a gas turbine engine according to an embodiment of the present invention.

FIG. 2 is an aft view of one embodiment of a synchronizing ring with bumpers including a surge bumper assembly.

FIG. 3 is a perspective view of a portion of the synchronizing ring and the surge bumper assembly of FIG. 2.

FIG. 4 is an exploded view of surge bumper assembly of FIG. 3.

FIG. 5A is a perspective view of a second embodiment of a surge bumper assembly.

FIG. 5B is a perspective view of the surge bumper assembly of FIG. 5A.

FIG. 6 is an exploded view of a third embodiment of a surge bumper assembly.

DETAILED DESCRIPTION

The present application discloses a surge bumper assembly that is part of a synchronizing ring assembly for a gas turbine engine. The surge bumper assembly includes a bracket that is riveted or otherwise connected to the synchronizing ring adjacent a split in the synchronizing ring. A composite pad is riveted or otherwise connected to the bracket so as to be disposed between the bracket and a case of the gas turbine engine.

A gas turbine engine generally includes an engine case, a compressor and turbine section. A typical compressor has multiple variable guide vanes, synchronizing ring assemblies with adjustable bumpers. These can be used in either or both the high pressure compressor (HPC) as well as the low pressure compressor (LPC) sections of the gas turbine engine. The gas turbine engine illustrated in this application illustrates variable guide vanes, synchronizing ring assembly with adjustable bumper assemblies, and a surge bumper assembly used in the HPC by way of example. It should be understood that the variable guide vanes, synchronizing ring assembly with adjustable bumper assemblies, and a surge bumper assembly can alternatively or additionally be used in the LPC section of the gas turbine engine as well.

During certain operation conditions (e.g., surge), the surge bumper assembly minimizes excessive radial deflection (chording) of the synchronizing ring assembly. This allows the synchronizing ring assembly to achieve more precise alignment and positioning of variable vanes as well as reducing stresses on the synchronizing ring assembly. The compact design of the surge bumper assembly allows it to be disposed in locations where other conventional bumpers are unable to fit. Additionally, the surge bumper assembly provides for a simplified easily installable design relative to conventional bumpers.

FIG. 1 is a cross-sectional view of a compressor section of a gas turbine engine 10 that includes a plurality of rotatable variable guide vanes (VGV) 12a- 12d, a plurality of rotor blades 14, an engine case 18, vane arms 20a-20d, synchronizing ring assemblies 22a- 22d, and bumpers 24a-24d. Although FIG. 1 references the compressor section principles of the present invention may be applied to a turbine section of a gas turbine engine as well.

In the embodiment shown in FIG. 1, VGVs 12a-12d comprise stages 1-3 VGVs 12a- 12c and inlet guide vane (IGV) 12d. With respect to VGVs 12a-12c, each is rotatable about an axis 16 that is substantially perpendicular with engine centerline axis C _L - With respect to IGV 12d, IGV 12d is rotatable about an axis 16. The performance of gas turbine engine 10 is modified, in part, by adjusting the position of stationary VGVs 12a-12d to selectively vary airflow characteristics of the engine.

The mechanical force used to change the position of VGVs 12a-12d is provided by an actuator (not shown), and is communicated via an assembly of linkages (not shown) to VGVs 12a- 12d via synchronizing ring assemblies 22a- 22d and vane arms 20a-20d.

The actuator and linkages (not shown) are positioned radially outward of engine case 18. Synchronizing ring assemblies 22a-22d are disposed around the engine case 18 and are mounted on bumpers 24a-24d. Thus, bumpers 24A-24d are disposed at various locations around the inner circumference of synchronizing ring assemblies 22a-22d between synchronizing ring assemblies 22a-22d and engine case 18.

Linkages (not shown) are connected to synchronizing ring assemblies 22a- 22d. During operation, linkages are actuated to move synchronizing ring assemblies 22a- 22d and cause them to slide relative to engine case 18 on bumpers 24a- 24d. Vane arms 20a- 20d are mounted to synchronizing ring assemblies 22a- 22d and extend to connect to trunnion portions of VGVs 12a-12d that protrude from engine case 18. Circumferential and translational movement of the synchronizing ring assemblies 22a-22d relative to engine case 18 causes vane arms 20a-20d to move thereby causing VGVs 12a-12d to pivot about axes 16.

FIG. 2 is an aft view of synchronizing ring assembly 22a from along engine centerline axis C _L - FIG. 3 is a perspective view of a portion of synchronizing ring assembly 22a and vane arms 20a. In FIG. 2, components such as engine case 18 and VGVs 12a-12d are not shown. In addition to bumpers 24a, synchronizing ring assembly 22a includes a surge bumper assembly 26 and splice brackets 28a and 28b. FIG. 3 illustrates vane arms 20a, a ring section 25a, surge bumper 26, a gap 27a, a splice bracket 28a, a first side surface 29a and an inner radial surface 31a.

As shown in FIG. 2, synchronizing ring assembly 22a extends generally circumferentially around engine centerline axis C _L - Bumpers 24a are disposed along inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a at various locations. In the embodiment shown, synchronizing ring assembly 22a is split in half with two arcuate ring sections 25a and 25b. These ring sections 25a and 25b are disposed adjacent one another spaced at gaps 27a and 27b. Surge bumper assembly 26 is connected via generally axially extending rivets (with respect to engine centerline axis C _L ) to first side surface 29a (FIG. 3) of synchronizing ring assembly 22a and extends to be positioned adjacent inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a near casing 18 (FIG. 1). In the embodiment shown, surge bumper assembly 26 is disposed on ring section 25a adjacent gap 27a. Splice brackets 28a and 28b are disposed radially outward of ring sections 25 a and 25b and connect ring sections 25 a and 25b together. Although only one surge bumper assembly 26 is illustrated in FIGS. 2 and 3, in other embodiments multiple surge bumper assemblies can be utilized.

FIG. 4 shows an exploded view of surge bumper assembly 26. Surge bumper assembly 26 includes bracket 30, rivets 33a and 33b, pad 36, and rivets 38a and 38b. Bracket 30 includes mounting portion 32, main body 35, flanges 34a and 34b and a pad seating portion 34.

Fasteners such as rivets 33a and 33b are adapted to be received in mounting portion 32 of bracket 30. Main body 35 and flanges 34a and 34b together form pad seating portion 34 that extends generally perpendicularly from mounting portion 32. Flanges 34a and 34b are arranged on either end of main body 35 and are adapted to receive rivets 38a and 38b. Pad 36 is comprised of a composite material and is adapted to mount to an inner radial surface 37 of bracket 30 and is connected thereto by fasteners such as rivets 38a and 38b. In one embodiment, pad 36 is comprised of a reinforced polyimide resin such as CP-0301 manufactured by DuPont Corporation of Wilmington, DE.

Rivets 33a and 33b are adapted to extend generally axially with respect to engine centerline axis C _L (FIGS. 1 and 2). In particular, mounting portion 32 of bracket 30 is adapted to receive rivets 33a and 33b, which additionally extend into first side surface 29a of ring section 25a (FIG. 3). Main body 35 and flanges 34 extend from mounting portion 32 and are adapted to be received in a recess of ring section 25a (FIG. 3). Rivets 38a and 38b are adapted to extend generally radially with respect to engine centerline axis C _L (FIGS. 1 and 2) to connect pad 36 to bracket 30. In one embodiment, pad 36 extends radially from bracket 30 to be flush with or protrude from inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a (FIGS. 2 and 3). During certain operation conditions (e.g., surge), the surge bumper assembly 26 contacts engine case 18 (FIG. 1) to minimize excessive radial deflection (chording) of the synchronizing ring assembly 22a (FIGS. 2 and 3).

FIGS. 5A and 5B show views of a second embodiment of surge bumper assembly 126. Surge bumper assembly 126 includes bracket 130, rivets 133a and 133b, pad 136, and rivets 138a and 138b. Bracket 130 includes a mounting portion 132 and a pad seating portion 134.

Fasteners such as rivets 133a and 133b are adapted to be received in mounting portion 132 of bracket 130. Pad seating portion 134 extends generally perpendicularly from mounting portion 132 and is adapted to receive rivets 138a and 138b. Pad 136 is adapted to mount to an inner radial surface 137 of bracket 130 and is connected thereto by fasteners such as rivets 138a and 138b. In the embodiment shown in FIGS. 5A and 5B, pad 136 includes portions 140a and 140b that are thinner than main body 142.

Rivets 133a and 133b are adapted to extend generally axially with respect to engine centerline axis C _L (FIGS. 1 and 2). In particular, mounting portion 132 of bracket 130 is adapted to receive rivets 133a and 133b, which additionally extend into first side surface 29a of ring section 25a (FIG. 3). ). Rivets 138a and 138b are adapted to extend generally radially with respect to engine centerline axis C _L (FIGS. 1 and 2) to connect pad 136 to bracket 130. Pad seating portion 134 extends from mounting portion 132 and is adapted to be received in a recess of ring section 125a (FIG. 3). In one embodiment, pad 136 extends radially from bracket 130 to be flush with or protrude from inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a (FIGS. 2 and 3). During certain operation conditions (e.g., surge), the surge bumper assembly 126 contacts engine case 18 (FIG. 1) to minimize excessive radial deflection (chording) of the synchronizing ring assembly 22a (FIGS. 2 and 3).

FIG. 6 shows an exploded view of yet another embodiment of a surge bumper assembly 226. Surge bumper assembly 226 includes bracket 230, rivets 233a and 233b, pad 236, and rivets 238a and 238b. Bracket 230 includes mounting portion 232 and pad seating portion 234. Pad 236 includes a main body 242. Pad seating portion 234 includes a hole 244.

Fasteners such as rivets 233a and 233b are adapted to be received in mounting portion 232 of bracket 230. Pad seating portion 234 extends generally perpendicularly from mounting portion 232. Pad seating portion 234 is adapted to receive rivets 238a and 238b. Pad 236 is adapted to mount flush to the pad seating portion 234 of bracket 230 and is connected thereto by fasteners such as rivets 238a and 238b. Pad 236 is adapted to mount flush to the inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a (FIGS. 2 and 3). In the embodiment shown in FIG. 6, pad 236 includes thickened main body 242 that is adapted to extend through hole 244 in bracket 240.

Rivets 233a and 233b are adapted to extend generally axially with respect to engine centerline axis C _L (FIGS. 1 and 2). In particular, mounting portion 232 of bracket 230 is adapted to receive rivets 233a and 233b, which additionally extend into first side surface 29a of ring section 25a (FIG. 3). Pad seating portion 234 extends from mounting portion 232 and is adapted to be received in a recess of ring section 25a (FIG. 3). Rivets 238a and 328b are adapted to extend generally radially with respect to engine centerline axis C _L (FIGS. 1 and 2) to connect pad 236 to bracket 230. In one embodiment, pad 236 extends radially from bracket 230 to be flush with or protrude from inner radial surface 31a (FIG. 3) of synchronizing ring assembly 22a (FIGS. 2 and 3). During certain operation conditions (e.g., surge), the surge bumper assembly 226 contacts engine case 18 (FIG. 1) to minimize excessive radial deflection (chording) of the synchronizing ring assembly 22a (FIGS. 2 and 3).

The present application discloses a surge bumper assembly that is part of a synchronizing ring assembly for a gas turbine engine. The surge bumper assembly includes a bracket that is riveted or otherwise connected to the synchronizing ring adjacent a split in the synchronizing ring. A composite pad is riveted or otherwise connected to the bracket so as to be disposed between the bracket and a case of the gas turbine engine.

During certain operation conditions (e.g., surge), the surge bumper assembly minimizes excessive radial deflection (chording) of the synchronizing ring assembly. This allows the synchronizing ring assembly to achieve more precise alignment and positioning of variable vanes as well as reducing stresses on the synchronizing ring assembly. The compact design of the surge bumper assembly allows it to be disposed in locations where other conventional bumpers are unable to fit. Additionally, the surge bumper assembly provides for a simplified easily installable design relative to conventional bumpers.

While the invention has been described with reference to an exemplary embodiment(s), 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 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(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the pad is mounted on at least one of an inner radial surface or outer radial surface of the bracket.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the pad is mounted to an outer radial surface of the bracket, and wherein a portion of pad extends through a hole in the bracket.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the first rivet comprises two rivets that extend through opposing ends of the pad from one another.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the bracket includes a mounting portion and a pad seating portion, and wherein the mounting portion extends generally perpendicularly with respect to the pad seating portion.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include a synchronizing ring assembly, and wherein the mounting portion is adapted to interface and mount to a side surface of the synchronizing ring assembly.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include a second rivet that is disposed generally perpendicular to the first rivet, wherein the second rivet extends through the mounting portion of the bracket to connect the bracket to the synchronizing ring.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the bumper assembly comprises a surge bumper assembly.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include a pad connected to the bracket

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the pad is mounted on at least one of an inner radial surface or outer radial surface of the bracket.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include wherein the pad is connected to the bracket by a first rivet.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include a second rivet that is disposed generally perpendicularly to the first rivet, wherein the second rivet extends through a mounting portion of the bracket to connect the bracket to the synchronizing ring and the first rivet connects the pad to a pad seating portion of the bracket.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the bracket includes a pad seating portion and a mounting portion, and wherein the pad seating portion receives the pad thereon and extends generally perpendicularly to the mounting portion.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the pad is mounted on at least one of an inner radial surface or outer radial surface of the bracket.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include a surge bumper assembly with a bracket and a pad connected to the bracket, the pad is connected to the bracket by a first rivet that extends generally radially with respect to a centerline axis of the gas turbine engine.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the surge bumper assembly is connected to the first side surface of the synchronizing ring assembly by a second rivet that extends generally axially with respect to a centerline axis of the gas turbine engine.

In a further embodiment of any of the foregoing embodiments, the assembly and/or gas turbine engine may additionally or alternatively include the surge bumper assembly comprises a split rings, and wherein the surge bumper assembly is disposed adjacent a gap at an end of one of the ring sections.