Structural guide vane for gas turbine engine

A guide vane for use in a gas turbine engine fan section has an airfoil extending between a radially inner platform and a radially outer platform. The radially inner platform has a radially outwardly facing surface from which the airfoil extends and a radially inwardly facing underside. The airfoil has a trailing edge extending to a leading edge. The underside is attached to a mount bracket and a main rib extending from the underside of the platform adjacent the trailing edge and in a direction generally towards the leading edge, and merging into a top surface on the mount bracket. A pair of shoulders is formed on each of two circumferential sides of the rib. Each of the shoulders is spaced from each other at a point on the shoulders connected into the top surface of the mount bracket. The shoulders extend circumferentially toward each other and the under surface.

BACKGROUND

This application relates to a structural guide vane for use in a gas turbine engine.

Gas turbine engines are known and, when utilized on an aircraft, they typically include a fan delivering air into a compressor and into a bypass duct defined by a nacelle. Downstream of the fan, there is typically a row of structural guide vanes, which extend between a core engine housing radially outwardly to an inner surface of the nacelle.

Historically, a turbine drove a compressor section and a fan rotor at a common speed. More recently, a gear reduction has been provided between a fan drive turbine and the fan rotor. This allows the fan to rotate at slower speeds and has further allowed an increase in the fan diameter.

As the fan diameter increases, a bypass ratio or the volume of air delivered into the bypass duct, compared to the volume of air delivered into the compressor, has increased dramatically. With this dramatic increase in the fan diameter and the bypass ratio, the radial length of the guide vanes has increased. To reduce weight, these guide vanes have become structural.

SUMMARY

In a featured embodiment, a guide vane for use in a gas turbine engine fan section has an airfoil extending between a radially inner platform and a radially outer platform. The radially inner platform has a radially outwardly facing surface from which the airfoil extends and a radially inwardly facing underside. The airfoil has a trailing edge extending to a leading edge. The underside is attached to a mount bracket and a main rib extending from the underside of the inner platform adjacent to the trailing edge and in a direction generally towards the leading edge, and merging into a top surface on the mount bracket. A pair of shoulders is formed on each of two circumferential sides of the main rib. Each of the shoulders is spaced from each other at a point on the shoulders connected into the top surface of the mount bracket. The shoulders extend circumferentially toward each other and toward the under surface.

In another embodiment according to the previous embodiment, the shoulders have a first portion extending toward an opposed first portion of the other of the shoulders. A second portion extends generally radially outwardly to merge into the underside of the inner platform. The second portion of the two shoulders is closer to parallel than are the first portions.

In another embodiment according to any of the previous embodiments, the main rib is radially thinner adjacent the trailing edge than it is at a location where it merges into the top surface of the mount bracket.

In another embodiment according to any of the previous embodiments, the main rib extends beyond the shoulders and the mount bracket in a direction toward the trailing edge.

In another embodiment according to any of the previous embodiments, the underside is formed with a rib extension extending from the mount bracket in a direction toward the leading edge. The rib extension extends toward the leading edge and has a central web merging into a Y-shaped pair of webs, and then to a pair of bolt holes.

In another embodiment according to any of the previous embodiments, a forward web connects the bolt holes.

In another featured embodiment, a fan section has a fan rotor and blades. At least one guide vane includes an airfoil extending between a radially inner platform and a radially outer platform. The radially inner platform has a radially outwardly facing surface from which the airfoil extends and a radially inwardly facing underside. The airfoil has a trailing edge extending to a leading edge. The underside is attached to a mount bracket and a main rib extending from the underside of the inner platform adjacent the trailing edge and in a direction generally towards the leading edge, and merging into a top surface on the mount bracket. A pair of shoulders is formed on each of two circumferential sides of the main rib. Each of the shoulders is spaced from each other at a point on the shoulders connected into the top surface of the mount bracket. The shoulders extend circumferentially toward each other and toward the under surface.

In another embodiment according to the previous embodiment, the shoulders have a first portion extending toward an opposed first portion of the other of the shoulders. A second portion extends generally radially outwardly to merge into the underside of the inner platform. The second portions of the two shoulders are closer to parallel than are the first portions.

In another embodiment according to any of the previous embodiments, the main rib is radially thinner adjacent the trailing edge than it is at a location where it merges into the top surface of the mount bracket.

In another embodiment according to any of the previous embodiments, the main rib extends beyond the shoulders and the mount bracket in a direction toward the trailing edge.

In another embodiment according to any of the previous embodiments, the underside is formed with a rib extension extending from the mount bracket in a direction toward the leading edge. The rib extension extends toward the leading edge and has a central web merging into a Y-shaped pair of webs, and then to a pair of bolt holes.

In another embodiment according to any of the previous embodiments, a forward web connects the bolt holes.

In another featured embodiment, a gas turbine engine has a compressor, a turbine, a fan section, a fan rotor and blades, and a nacelle defining a bypass duct, and at least one guide vane in the bypass duct. The guide vane includes an airfoil extending between a radially inner platform and a radially outer portion. The radially inner platform has a radially outwardly facing surface from which the airfoil extends and a radially inwardly facing underside. The airfoil has a trailing edge extending to a leading edge. The underside is attached to a mount bracket and a main rib extending from the underside of the inner platform adjacent the trailing edge and in a direction generally towards the leading edge, and merging into a top surface on the mount bracket. A pair of shoulders is formed on each of two circumferential sides of the main rib. Each of the shoulders is spaced from each other at a point on the shoulders connected into the top surface of the mount bracket. The shoulders extend circumferentially toward each other and toward the under surface.

In another embodiment according to the previous embodiment, the shoulders have a first portion extending toward an opposed first portion of the other of the shoulders. A second portion extends generally radially outwardly to merge into the underside of the inner platform. The second portions of the two shoulders are closer to parallel than are the first portions.

In another embodiment according to any of the previous embodiments, the main rib is radially thinner adjacent the trailing edge than it is at a location where it merges into the top surface of the mount bracket.

In another embodiment according to any of the previous embodiments, the main rib extends beyond the shoulders and mount bracket in a direction toward the trailing edge.

In another embodiment according to any of the previous embodiments, the underside is formed with a rib extension extending from the mount bracket in a direction toward the leading edge. The rib extension extends toward the leading edge and has a central web merging into a Y-shaped pair of webs, and then to a pair of bolt holes.

In another embodiment according to any of the previous embodiments, a forward web connects the bolt holes.

DETAILED DESCRIPTION

The core airflow is compressed by the low pressure compressor44then the high pressure compressor52, mixed and burned with fuel in the combustor56, then expanded over the high pressure turbine54and low pressure turbine46. The mid-turbine frame57includes airfoils59which are in the core airflow path. The turbines46,54rotationally drive the respective low speed spool30and high speed spool32in response to the expansion.

A fan guide vane58is illustrated inFIG. 2. As known, an airfoil82extends from a radially inner platform74to a radially outer platform100. Platform100is shown schematically in this view. The airfoil82extends from a trailing edge83to a leading edge85. The platform74has a radially outward facing surface76and the airfoil82extends from that surface. A radially underside surface78of the platform74receives a mount bracket60. Bolt holes75are formed in the mount bracket60.

A rib89extends radially outwardly of the underside78and at an angle such that it is thinnest at a point71adjacent a trailing edge of the platform74, and gets thicker before merging into an upper or top surface51of the mount bracket60adjacent a point73. A shoulder70is shown on one circumferential side of the rib89. The rib89has a side84spaced away from the shoulder70. The rib extends beyond shoulders70/72and the mount bracket60in a direction toward trailing edge83.

FIG. 3is a rear view of the guide vane58. As shown, the rib89has extensions91and86, extending forwardly toward the leading edge. The shoulder70is provided on one side of the rib89and a matching shoulder72is formed on an opposed circumferential side.

As can be seen, the two shoulders70,72are spaced closer to each other at a point171at which they merge into the platform underside78, and spaced further from each other at a point69where they connect into the top surface51of mount bracket60.

The shoulders have a first portion200extending in a circumferential direction towards each other, and then a straight portion183extending generally parallel to each other, and merging into the underside78. The portions183may not be exactly parallel, but they are closer to being parallel than are portions200.

The structure of the shoulders70,72, thus, is softer at the point171at which it merges into the platform surface78, and stiffer at portions200extending along the mount bracket60. The softer structure adjacent point171allows for a better reception of the stresses from the airfoil82, while the stiffer surface adjacent area200provides better side to side or circumferential bending support.

FIG. 4schematically shows the vane58mounted within a gas turbine engine structure. As shown, a compressor case300and206is mounted adjacent to the ends of platform74. As can be seen, the rib89has a portion189extending forwardly and which is curved at191. Bracket204is shown schematically and will bolt to the mount bracket60to secure vane58to the compressor case206/300. A second bracket202bolts to a forward end203of the guide vane58.

FIG. 5shows the underside of the guide vane58. As shown, the rib portion189extends toward a leading edge from a trailing edge83of the airfoil. There is a Y-shaped structure formed by webs91/86extending from a central web291of the rib portion189, and extending to bolt holes88which are connected by a rib90. The bolt holes88receive bolts to attach to the bracket202(seeFIG. 4).

The guide vane58as disclosed in this application, thus, provides efficient support and reaction against the forces it will see when in use.