Patent Description:
Gas turbine engines are known and typically include a fan delivering air into a bypass duct as bypass air and into a compressor as core air. The air is compressed and delivered into a combustor section where the air is mixed with fuel and ignited. Products of the combustion pass downstream over turbine rotors, which causes the turbine rotors to rotate.

Gas turbine engines require specific support stiffnesses and/or oil feed dampers to manage vibrations of rotating and static structures at specific operating speeds. In one configuration, a centering spring is used in combination with an oil damper that is positioned between a bearing outer race and a static engine structure. The oil damper comprises an oil squeeze film damper made from a plurality of segments that are mounted directly between the outer race and the engine static structure. The centering spring extends axially away from one end of the film damper to a distal end that is fixed to the static engine structure. While this configuration is effective at managing vibrations, a significant amount of axial space is consumed by the centering spring and damper. Additionally, the centering spring and damper are expensive and complicated to machine due to the large number of tightly controlled surfaces to manage stress and stiffness for a given amount of deflection. Curved beam dampers can also be used to dampen vibrations; however, this configuration is not conducive for providing an effective and reliable oil film damper.

<CIT> discloses a rolling bearing radial support having a nonlinear stiffness.

<CIT> discloses a damping system for use in rotating machinery.

<CIT> discloses a support for oil film dampers.

In accordance with a first aspect of the disclosure, a gas turbine engine component is provided in accordance with claim <NUM>.

In another embodiment according to any of the previous embodiments, the bearing includes an inner race fixed for rotation with a shaft about the engine center axis, the outer race is fixed to the outer support structure, rolling elements are received between the inner and outer races, and a bearing housing surrounds the outer race to form a plurality of fluid damping chambers between the bearing housing and the outer race that are sealed by one or more piston rings or o-rings to provide the fluid damper.

In another embodiment according to any of the previous embodiments, the outer race is mounted to the outer support structure and the bearing housing is supported by the flange of the engine static structure.

In another embodiment according to any of the previous embodiments, the curved beam has an outer peripheral surface and an inner peripheral surface surrounding the engine center axis, and wherein the plurality of curved beam spring segments are circumferentially positioned adjacent to each other to form the ring, and wherein the inner and outer support structures surround the curved beam such that the outer peripheral surface of the curved beam faces an inner surface of the outer support structure and the inner peripheral surface of the curved beam faces an outer surface of the inner support structure.

In another embodiment according to any of the previous embodiments, each curved beam spring segment includes an arcuate body having at least one outer damper pedestal extending radially outward of an outer peripheral surface of the arcuate body and at least one inner damper pedestal extending radially inward of an inner peripheral surface of the arcuate body, and wherein the outer damper pedestal is engageable with the outer support structure and the inner damper pedestal is engageable with the inner support structure.

In another embodiment according to any of the previous embodiments, each arcuate body extends circumferentially from a first end to a second end that is opposite the first end, and wherein the at least one outer damper pedestal is positioned centrally between the first and second ends, and wherein the at least one inner damper pedestal comprises at least a first inner damper pedestal adj acent the first end and a second inner damper pedestal adjacent to the second end.

In another embodiment according to any of the previous embodiments, the outer support structure comprises a first ring-shaped structure with a first set of tabs and a first set of slots, and wherein the inner support structure comprises a second ring-shaped structure with a second set of tabs and a second set of slots, and wherein the inner and outer structures are coupled together by inserting the second set of tabs through the first set of slots and by inserting the first set of tabs through the second set of slots.

In another embodiment according to any of the previous embodiments, the plurality of curved beam spring segments comprises at least <NUM> segments.

In another embodiment according to any of the previous embodiments, a squeeze film damper is associated with the bearing.

In another embodiment according to any of the previous embodiments, the bearing housing is supported by the engine static structure.

In another embodiment according to any of the previous embodiments, the outer support structure includes a first mount interface that is attached to the outer race and the inner support structure includes a second mount interface that is attached to the flange.

In another embodiment according to any of the previous embodiments, wherein an outer surface of the bearing housing is radially aligned with and spaced apart from the mechanical spring assembly by a gap.

The low speed spool <NUM> generally includes an inner shaft <NUM> that interconnects a first (or low) pressure compressor <NUM> and a first (or low) pressure turbine <NUM>. The inner shaft <NUM> is connected to a fan <NUM> through a speed change mechanism, which in exemplary gas turbine engine <NUM> is illustrated as a geared architecture <NUM> to drive the fan <NUM> at a lower speed than the low speed spool <NUM>.

<FIG> shows an example of an axially rigid curved beam and a fluid damper that cooperate to provide support stiffness and damping to manage vibrations of associated rotating and static structures at specific engine operating speeds. At least one bearing <NUM> supports a rotating structure <NUM>, such as a shaft for example, for rotation relative to an engine static structure <NUM>, such as a case structure, for example. The bearing <NUM> includes an outer race <NUM>, an inner race <NUM>, and one or more rolling elements <NUM> between the inner <NUM> and outer <NUM> races. The inner race <NUM> is fixed for rotation with the shaft <NUM> and the outer race is fixed to the engine static structure <NUM>.

An assembly <NUM> that comprises an axially rigid curved beam is installed radially outward of the bearing <NUM>. The assembly <NUM> includes an outer support structure <NUM> fixed to the engine static structure <NUM>, an inner support structure <NUM> surrounding the engine center axis A and fixed to the engine static structure <NUM>, and a curved beam comprised of a plurality of curved beam spring segments <NUM> that are positioned adjacent to each other to form a ring as shown in <FIG>. The inner <NUM> and outer <NUM> support structures are coupled together around the curved beam spring segments <NUM> of the curved beam to enclose the curved beam therebetween and form the assembly <NUM>. The bearing <NUM> is spaced radially inward of the assembly such that there is a compartment <NUM> between the assembly <NUM> and the bearing <NUM>.

As shown in <FIG>, a fluid damper <NUM> is spaced radially inward of the inner support structure <NUM> of the assembly <NUM>. In one example, the fluid damper <NUM> comprises an oil squeeze film damper. The bearing <NUM> includes a bearing housing <NUM> surrounding the outer race <NUM> to form a plurality of fluid damping chambers <NUM> between the bearing housing <NUM> and the outer race <NUM> that are sealed by one or more piston rings or o-rings <NUM> to provide the fluid damper <NUM>. Fluid flows through the chambers <NUM> via a fluid inlet and outlet (not shown) to provide damping as known. An outer surface of the bearing housing <NUM> is radially aligned with and spaced apart from the assembly <NUM> by the compartment <NUM>.

The outer support structure <NUM> is fixed to the outer race <NUM> and the inner support structure <NUM> is fixed to a flange <NUM> of the engine static structure <NUM>. The bearing housing <NUM> is supported by the engine static structure <NUM>.

As shown in <FIG>, the plurality of curved beam spring segments <NUM> that form a ring have an outer peripheral surface <NUM> and an inner peripheral surface <NUM> surrounding the engine center axis A. The plurality of curved beam spring segments <NUM> are circumferentially positioned adjacent to each other end-to-end to form the ring. The inner <NUM> and outer <NUM> support structures surround the curved beam spring segments <NUM> such that the outer peripheral surface <NUM> of the curved beam faces an inner surface <NUM> of the outer support structure <NUM> and the inner peripheral surface <NUM> of the curved beam faces an outer surface <NUM> of the inner support structure <NUM>.

<FIG> show the inner <NUM> and outer <NUM> support structures coupled together to form the assembly <NUM>. In one example, the inner support structure <NUM> includes a ring body <NUM> with a mounting flange <NUM> at one edge of the ring body <NUM> that forms a mount interface that is attached to one of the flange <NUM> of the engine static structure <NUM>. In this example, the mounting flange <NUM> extends radially outwardly of the ring body <NUM>. The mounting flange <NUM> includes a plurality of openings <NUM> configured to receive fasteners (not shown) to secure the inner support structure <NUM> to the flange <NUM>. In one example, the outer support structure <NUM> includes a ring body <NUM> with a mounting flange <NUM> at one edge of the ring body <NUM> that forms a mount interface that is attached to the bearing outer race <NUM>. In this example, the mounting flange <NUM> extends radially inwardly of the ring body <NUM>. The mounting flange <NUM> includes a plurality of openings <NUM> configured to receive fasteners (not shown) to secure the outer support structure <NUM> to the bearing outer race <NUM>. In the view of <FIG>, the curved beam spring segments <NUM> are shown sandwiched between the inner <NUM> and outer <NUM> support structures.

<FIG> shows the curved beam that forms a ring <NUM>, which is comprised of the curved beam spring segments <NUM>, while <FIG> show an example of one of the curved beam spring segments <NUM>. Each curved beam spring segment <NUM> includes an arcuate body <NUM> with an outer surface that forms a portion of the outer peripheral surface <NUM> of the ring <NUM> and an inner surface that forms a portion of the inner peripheral surface <NUM> of the ring <NUM>. The arcuate body <NUM> includes at least one outer damper pedestal <NUM> extending radially outward of the outer peripheral surface <NUM> of the arcuate body <NUM>, and at least one inner damper pedestal <NUM> extending radially inward of the inner peripheral surface <NUM> of the arcuate body <NUM>. The outer damper pedestal <NUM> faces and is engageable with the outer support structure <NUM> and the inner damper pedestal <NUM> faces and is engageable with the inner support structure <NUM>.

Each arcuate body <NUM> extends circumferentially from a first end <NUM> to a second end <NUM> that is opposite the first end <NUM> as shown in <FIG>. In one example, the outer damper pedestal <NUM> is positioned centrally between the first <NUM> and second ends <NUM>. In one example, the inner damper pedestal <NUM> comprises at least a first inner damper pedestal <NUM> adjacent the first end <NUM> and a second inner damper pedestal <NUM> adjacent to the second end <NUM>. In one example, there are ten curved beam spring segments <NUM>. In other configurations, the number of curved beam spring segments <NUM> can be increased or decreased, and/or the number of outer <NUM> and inner <NUM> pedestals can be increased or decreased, and can be varied in position, to provide a desired stiffness.

As shown in <FIG>, the outer support structure <NUM> comprises a first ring-shaped structure that forms the ring body <NUM>. The ring body <NUM> has a width that extends from a first edge <NUM> to an opposite second edge <NUM>. In one example, a first set of tabs <NUM> is formed at the first edge <NUM> and a first set of slots <NUM> is formed at the second edge <NUM>. In one example, the slots <NUM> are formed at an intersection of the ring body <NUM> and the radially inward mounting flange <NUM>. The inner support structure <NUM> comprises a second ring-shaped structure that forms the ring body <NUM>. The ring body <NUM> has a width that extends from a first edge <NUM> to an opposite second edge <NUM>. In one example, the ring body <NUM> includes a second set of tabs <NUM> formed at the first edge <NUM> and a second set of slots <NUM> formed at the second edge <NUM>. In one example, the slots <NUM> are formed at an intersection of the ring body <NUM> and the radially outward mounting flange <NUM>.

The inner <NUM> and outer <NUM> structures are coupled together by inserting the second set of tabs <NUM> through the first set of slots <NUM> and by inserting the first set of tabs <NUM> through the second set of slots <NUM>. This is best shown in <FIG>. In these section views, the spring elements <NUM> are completely enclosed within an open space <NUM> that is provided between the overlapping ring bodies <NUM>, <NUM> (<FIG>). In one example, clips (not shown) are received in grooves formed immediately adjacent to the tabs <NUM>, <NUM> and outboard of the flanges <NUM>, <NUM> to axially retain the assembly together. This connection interface between the inner <NUM> and outer <NUM> support structures, and around the curved beam ring <NUM>, provides for axial rigidity in a direction along the engine center axis A.

The subject disclosure provides a configuration with a mechanical spring assembly <NUM> that is separated from a fluid damper <NUM>. While the curved beam ring <NUM> is radially compliant, the assembly <NUM> also provides the capability of withstanding bilateral thrust loading. The ring <NUM> also offers the ability to tune stiffness as needed by varying the number of outer <NUM> and inner <NUM> pedestals. The thickness and axial width of the spring segments <NUM> can also be varied as needed to provide a desired stiffness. By separating the fluid damper and mechanical spring, and with radially aligning the fluid damper and the mechanical spring, a very compact configuration is provided with increased available space as compared to prior centering spring and damper designs.

Claim 1:
A gas turbine engine component comprising:
an inner support structure (<NUM>) surrounding an engine center axis (A) and fixed to an engine static structure (<NUM>);
an outer support structure (<NUM>) spaced radially outward of the inner support structure (<NUM>);
a curved beam comprised of a plurality of curved beam spring segments (<NUM>) that are positioned adjacent to each other to form a ring (<NUM>), and wherein the inner and outer support structures (<NUM>, <NUM>) are coupled together around the curved beam to enclose the curved beam therebetween and form a mechanical spring assembly (<NUM>); and
a bearing (<NUM>) spaced radially inward of the mechanical spring assembly (<NUM>); and
a fluid damper (<NUM>) that is separated from the mechanical spring assembly (<NUM>), wherein the fluid damper (<NUM>) is spaced radially inward of the inner support structure (<NUM>),
characterised in that:
the outer support structure (<NUM>) is fixed to an outer race (<NUM>) of the bearing (<NUM>) and the inner support structure (<NUM>) is fixed to a flange (<NUM>) of the engine static structure (<NUM>).