Patent Description:
Turbomachinery supported on hydrodynamic foil bearings typically requires a set of journal and thrust bearings to support radial and axial loads. Conical bearings support both radial and axial loads, which eliminates the need for thrust bearings. However, most foil journal bearings are cylindrical. Limited conical bearing designs, with cylindrical bores on either end of the sleeve, rely on uniform spring stiffness in a single or multipad configuration with limited capability to support dynamic operational loads.

<CIT> discloses a hydrodynamic fluid film bearing having a stationary retaining member having a cylindrical opening to receive for rotation therein a rotatable shaft. The inner surface of the opening is lined by a generally cylindrical-shaped foil assembly comprised of a plurality of foil sub-assemblies each comprised of spring foils, contact foils and, optionally, inner foils. Each foil sub-assembly subtends a rotational segment, less than all, of the inner surface, e.g., from about <NUM> degrees to <NUM> degrees of rotation. The spring foils and contact foils are affixed to the retaining member in such a way that sliding travel of the spring foils along the inner surface is in the opposite rotational direction of sliding travel of the contact foils along the inner surface. The foil sub-assemblies may be affixed to the retaining member by means of keyways within which the foil sub-assemblies are mounted.

As discussed herein, a conical bearing includes a bearing sleeve, a bump foil, and a top foil. The bearing sleeve extends along an axis from a first open end to a second open end. The bearing sleeve has an axially tapered shape such that a first open end diameter of the bearing sleeve is greater than a second open end diameter of the bearing sleeve. An interior surface of the bearing sleeve has a non-circular profile. The bump foil is concentrically disposed within the bearing sleeve with respect to the axis and includes a plurality of bump foil pad segments extending circumferentially about the interior surface of the bearing sleeve. Each bump foil pad segment comprises a plurality of foil bumps and the plurality of foil bumps varies in stiffness along a circumference of the bump foil. The top foil is concentrically disposed within the bump foil with respect to the axis and includes a plurality of top foil pad segments extending circumferentially about an interior surface of the bump foil.

The conical bearing of the preceding paragraph can optionally include, any one or more of the following features, configurations and/or additional components:.

A further embodiment of the foregoing conical bearing, wherein the plurality of foil bumps varies in height along the circumference of the bump foil.

A further embodiment of any of the foregoing conical bearings, wherein the plurality of foil bumps varies in pitch along the circumference of the bump foil.

A further embodiment of any of the foregoing conical bearings, wherein the plurality of foil bumps varies in height and pitch along the circumference of the bump foil.

A further embodiment of any of the foregoing conical bearings, wherein the bump foil is axially split such that the bump foil comprises a first bump foil section and a second bump foil section.

A further embodiment of any of the foregoing conical bearings, wherein each of the first bump foil section and the second bump foil section comprise three bump foil pad segments.

A further embodiment of any of the foregoing conical bearings, wherein each bump foil pad segment extends circumferentially about one third of the circumference of the bump foil.

A further embodiment of any of the foregoing conical bearings, wherein the top foil is axially split such that the top foil comprises a first top foil section and a second top foil section.

A further embodiment of any of the foregoing conical bearings, wherein each of the first top foil section and the second top foil section comprises three top foil pad segments.

A further embodiment of any of the foregoing conical bearings, wherein the bearing sleeve comprises a plurality of cooling channels extending axially along an exterior surface of the bearing sleeve.

A further embodiment of any of the foregoing conical bearings, further comprising a plurality of cooling holes extending radially outward through the bearing sleeve such that an interior end of each cooling hole is adjacent to an interior cavity of the conical bearing and an exterior end of each cooling hole is within a cooling channel.

As also discussed herein, a method of manufacturing a conical bearing includes manufacturing a bearing sleeve of the conical bearing such that the bearing sleeve extends about a central bearing sleeve cavity from a first open end to a second open end and has a tapered shape such that a first open end diameter of the bearing sleeve is greater than a second open end diameter of the bearing sleeve, and such that an interior surface of the bearing sleeve has a non-circular profile. A plurality of bump foil pad segments are manufactured, wherein each bump foil pad segment comprises a plurality of foil bumps and the plurality of foil bumps varies in stiffness along a length of the bump foil pad segment. A plurality of top foil pad segments are manufactured. The bump foil pad segments are assembled into a bump foil which extends about a central bump foil cavity from a first open end to a second open end and has a tapered shape such that a first open end diameter of the bump foil is greater than a second open end diameter of the bump foil. The top foil pad segments are assembled into a top foil which extends about a central top foil cavity from a first open end to a second open end and has a tapered shape such that a first open end diameter of the top foil is greater than a second open end diameter of the top foil. The bump foil is inserted into the central bearing sleeve cavity through the first open end of the bearing sleeve such that the bump foil is concentrically disposed within the bearing sleeve with respect to an axis about which the bearing sleeve extends. The top foil is inserted into the central bump foil cavity through the first open end of the bump foil such that the top foil is concentrically disposed within the bump foil with respect to the axis.

The method of the preceding paragraph can optionally include any one or more of the following features, configurations and/or additional components:.

A further embodiment of the foregoing method, wherein manufacturing the bearing sleeve comprises additively manufacturing the bearing sleeve.

A further embodiment of any of the foregoing methods, wherein additively manufacturing the bearing sleeve comprises forming at least one support slot in the interior surface of the bearing sleeve. Inserting the bump foil into the central bearing sleeve cavity comprises inserting a portion of at least one bump foil pad segment into the at least one support slot. Inserting the top foil into the central bump foil cavity comprises inserting a portion of at least one top foil pad segment into the at least one support slot.

A further embodiment of any of the foregoing methods, wherein additively manufacturing the bearing sleeve comprises forming at least one support dovetail in the interior surface of the bearing sleeve. Inserting the bump foil into the central bearing sleeve cavity comprises inserting a portion of at least one bump foil pad segment into the at least one support dovetail. Inserting the top foil into the central bump foil cavity comprises inserting a portion of at least one top foil pad segment into the at least one support dovetail.

A further embodiment of any of the foregoing methods, wherein additively manufacturing the bearing sleeve comprises forming a plurality of cooling channels in an exterior surface of the bearing sleeve.

A further embodiment of any of the foregoing methods, wherein additively manufacturing the bearing sleeve comprises forming a plurality of cooling holes extending radially outward through the bearing sleeve such that an interior end of each cooling hole is adjacent to the central bearing sleeve cavity and an exterior end of each cooling hole is within a cooling channel.

A further embodiment of any of the foregoing methods, wherein manufacturing the plurality of bump foil pad segments comprises shaping a sheet metal with a die to form the plurality of foil bumps, and wherein the plurality of foil bumps varies in height and pitch along the length of each bump foil pad segment according to an expected load exerted on the conical bearing by the shaft during rotation of the shaft.

The present summary is provided only by way of example, and not limitation. Other aspects of the present disclosure will be appreciated in view of the entirety of the present disclosure, including the entire text, claims, and accompanying figures.

While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings.

A conical bearing can incorporate foils, including a bump foil having varying bump pitch and/or bump height to better control bearing stiffness at locations which are expected to experience higher load during shaft rotation. The foils can be segmented and axially split for easier assembly. The bearing sleeve of the conical bearing can be additively manufactured to include features such as support slots or dovetails to retain the foil ends, anti-rotation tabs, cooling channels, and/or cooling holes. The cooling holes extending from the bearing sleeve's outer diameter to the inner diameter enable a hybrid bearing configuration for improved load-capacity of the bearing. The interconnecting holes further assist in heat dissipation from the bearing. The cooling channels on the outer diameter of the bearing sleeve can provide air flow passages to dissipate heat from the conical bearing via forced convection.

Each end of the conical bearing has a non-cylindrical inner diameter and can include a three-pad configuration. This allows the pads to be designed to control the geometry of each pad for offset. Additionally, the pads can be designed to be preloaded such that the center of curvature of the pad or lobe is not coincident with the geometric center of the bearing. Each lobe assists in hydrodynamic pressure generation from the leading edge to the trailing edge when the shaft is rotating counterclockwise. The sleeve inner diameter profile transitions from diverging to converging in order to assist in hydrodynamic pressure build up. The compliant bump foils on the leading edge engage with the bearing sleeve's inner diameter first. As the shaft speed increases along with the dynamic load, the bumps near the trailing edge start to become engaged with the sleeve, thus providing load support. In essence, bump foils compliance increases from leading to the trailing edge in the circumferential direction. The hydrodynamic air film thickness decreases from leading to the trailing edge. Additionally, the bump foils can be split axially along the length of the bearing to allow for improved bump foil stiffness. This axial split provides compliance to the dynamic load, minimizing foil deformation.

<FIG> are schematic sectional depictions of shaft system <NUM>. Shaft system <NUM> includes shaft <NUM> and bearing <NUM>. <FIG> is a schematic depiction of the load experienced by bearing <NUM> due to the rotation of shaft <NUM> within bearing <NUM>. <FIG> will be discussed in turn below.

As shown in <FIG>, shaft <NUM> rests on bearing <NUM> when shaft <NUM> is not rotating due to gravity. As shaft <NUM> begins to rotate (shown in <FIG>), it draws air and creates a hydrodynamic pressure wedge between the shaft <NUM> and bearing <NUM>. This hydrodynamic pressure wedge lifts shaft <NUM> off of the foil geometry of bearing <NUM>. <FIG> depicts the load W exerted by shaft <NUM> on bearing <NUM> and the hydrodynamic pressure P generated by bearing <NUM> during the rotation of shaft <NUM>. Hydrodynamic pressure P generated by bearing <NUM> varies at different points in the rotation of shaft <NUM>. Hydrodynamic pressure P is highest at particular points in the rotation of shaft <NUM> (which occur repeatedly at particular locations along bearing <NUM>). Hydrodynamic pressure typically increases along the leading edge <NUM> of the foil sections of bearing <NUM> and is greatest near the trailing edge <NUM> of each foil section (specifically, at or near point <NUM>, where the air film is also at a minimum). As described in more detail below, varying bump pitch and/or bump height, and axial split along the pad length within the foil geometry of bearing <NUM> allows for targeted dynamic stiffness control in these areas. This allows bearing liftoff to be more efficiently achieved, and bearing loading can be adjusted based on the expected loads and performance of the bearing.

<FIG> is a side view of conical bearing <NUM> about shaft <NUM> and disposed along axis X. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM> (shown in <FIG>), and top foil <NUM> (shown in <FIG>). Conical bearing <NUM> extends from inner end <NUM> to outer end <NUM> and includes exterior surface <NUM> and interior surface <NUM> (shown in <FIG>). In the example shown in <FIG>, bearing sleeve <NUM> includes cooling channels <NUM>. <FIG> is a perspective view of inner end <NUM> of conical bearing <NUM>. <FIG> is a perspective view of outer end <NUM> of conical bearing <NUM>. <FIG> will be discussed concurrently.

Conical bearing <NUM> has a hollow, axially tapered shape such that the diameter of a first open end (such as inner end <NUM>) is greater than the diameter of an opposite second open end (such as outer end <NUM>). Outer end <NUM> and inner end <NUM> are shaped such that a section of shaft <NUM> can extend through interior cavity <NUM> (shown in <FIG>) of conical bearing <NUM>. As described in more detail below in reference to FIGS. 6A-6C, the tapered shape of conical bearing <NUM> can support both radial and axial loads exerted by shaft <NUM> during rotation. In some examples, conical bearing <NUM> has a length of between approximately <NUM> inches (approximately <NUM> millimeters) and approximately <NUM> inches (approximately <NUM> millimeters).

Bearing sleeve <NUM> forms an outer layer of conical bearing <NUM> with respect to the location of shaft <NUM>. Bearing sleeve <NUM>, including cooling channels <NUM>, can be additively manufactured. Bump foil <NUM> forms a middle layer of conical bearing <NUM> and is located on the interior of bearing sleeve <NUM>, being concentrically disposed within bearing sleeve <NUM> with respect to axis X when conical bearing <NUM> is assembled. Top foil <NUM> forms an inside layer of conical bearing <NUM> and is adjacent to shaft <NUM>, and is concentrically disposed within bump foil <NUM> with respect to axis X when conical bearing <NUM> is assembled. Bump foil <NUM> and top foil <NUM> can be single wrap foils, such that each of bump foil <NUM> and top foil <NUM> form a single layer about shaft <NUM>. Bump foil <NUM> and top foil <NUM> can be formed of the same material. In some examples, bump foil <NUM> and top foil <NUM> are formed of a high-strength nickel-based alloy.

Bump foil <NUM> distributes the load exerted by shaft <NUM> on conical bearing <NUM> when shaft <NUM> rotates. As described in more detail below in reference to FIGS. 6A-6C, bump foil <NUM> can have a varying stiffness due to variations in bump geometry along bump foil <NUM>. Bump foil <NUM> can be formed out of a flat sheet and shaped with a die.

<FIG> is a partially exploded view of conical bearing <NUM>, and <FIG> is an exploded view of conical bearing <NUM> and shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM>. Conical bearing <NUM> extends from inner end <NUM> (shown in <FIG> and <FIG>) to outer end <NUM> (shown in <FIG> and <FIG>), and includes exterior surface <NUM> (shown in <FIG> and <FIG>) and interior surface <NUM> (shown in <FIG>). In the example depicted in <FIG>, bearing sleeve <NUM> includes cooling channels <NUM>. Bump foil <NUM> is axially split and includes first bump foil section <NUM> and second bump foil section <NUM> (both shown in <FIG>). Top foil <NUM> is axially split, and includes first top foil section <NUM> and second top foil section <NUM>. First bump foil section <NUM> and second bump foil section <NUM> can each include bump foil pad segments <NUM> (shown in <FIG>). First top foil section <NUM> and second top foil section <NUM> can each include top foil pad segments <NUM> (shown in <FIG>). Bearing sleeve <NUM> extends about central bearing sleeve cavity <NUM> from first open end <NUM> to second open end <NUM>. Bump foil <NUM> extends about central bump foil cavity <NUM> from first open end <NUM> to second open end <NUM>. Top foil <NUM> extends about central top foil cavity <NUM> from first open end <NUM> to second open end <NUM>. Exterior surface <NUM> of conical bearing <NUM> is the exterior surface of bearing sleeve <NUM>, and bearing sleeve <NUM> also includes interior surface <NUM>. Bump foil <NUM> has an exterior surface <NUM> and an interior surface <NUM>. Interior surface <NUM> of conical bearing <NUM> is the interior surface of top foil <NUM>, and top foil <NUM> also includes exterior surface <NUM>. <FIG> is a top plan view of outer end <NUM> of conical bearing <NUM>. <FIG> is a bottom plan view of inner end <NUM> of conical bearing <NUM>. <FIG> will be discussed concurrently below.

As described in more detail below in reference to <FIG>, the thickness of bearing sleeve <NUM> can vary to accommodate the shape of bump foil <NUM>, and interior surface <NUM> of bearing sleeve <NUM> can have a non-circular profile. In the example depicted in <FIG>, each of first bump foil section <NUM> and second bump foil section <NUM> includes three bump foil pad segments <NUM>. Similarly, each of first top foil section <NUM> and second top foil section <NUM> includes three top foil pad segments <NUM>. In some examples, bump foil pad segments <NUM> can be evenly circumferentially distributed such that each bump foil pad segment <NUM> makes up approximately one third of the circumference of bump foil <NUM>. Similarly, top foil pad segments <NUM> can be evenly circumferentially distributed such that each top foil pad segment <NUM> makes up approximately one third of the circumference of top foil <NUM>.

The stiffness of bump foil <NUM> can be varied circumferentially along the length of each bump foil pad section <NUM> (from the leading edge to the trailing edge). To increase bearing stiffness and damping, the bump foil pitch can be decreased from each leading edge to each trailing edge, the bump foil height can be increased from each leading edge to each trailing edge, or a combination of decreased pitch and increased height can be used. In these designs, the bearing assembly clearance can decrease from the leading edge to the trailing edge.

Both bump foil pad segments <NUM> and top foil pad segments <NUM> can be insertable into bearing sleeve <NUM> through central bearing sleeve cavity <NUM>. Top foil pad segments <NUM> can be insertable into bump foil pad segments <NUM> after bump foil pad segments <NUM> are assembled into bump foil <NUM> and/or inserted into bearing sleeve <NUM>. As described in more detail below in reference to <FIG>, each bump foil pad segment <NUM> and/or top foil pad segment <NUM> can include geometry which slots into, and is secured by, bearing sleeve support features.

<FIG> depicts method <NUM> of manufacturing a conical bearing (such as conical bearing <NUM> described above in reference to <FIG>). Method <NUM> includes steps <NUM>-<NUM>.

In step <NUM>, a bearing sleeve of the conical bearing is manufactured. The bearing sleeve can extend about a central bearing sleeve cavity (such as central bearing sleeve cavity <NUM>, shown in <FIG>) and can have a tapered shape such that the diameter of a first open end of the bearing sleeve (such as first open end <NUM> of bearing sleeve <NUM>, shown in <FIG>) is greater than the diameter of a second open end of the bearing sleeve (such as second open end <NUM> of bearing sleeve <NUM>, shown in <FIG>). The bearing sleeve can be additively manufactured and can, in some examples, include additively manufactured cooling channels and/or cooling holes. Additively manufacturing the bearing sleeve can include forming any of: at least one support slot in an interior surface of the bearing sleeve, at least one support dovetail in an interior surface of the bearing sleeve, a plurality of cooling channels in an exterior surface of the bearing sleeve, a plurality of cooling holes extending radially outward through the bearing sleeve such that an interior end of each cooling hole is adjacent to the central bearing sleeve cavity and an exterior end of each cooling hole is within a cooling channel, and/or any combination of forming these features. Additionally or alternatively, the cooling holes and/or cooling channels can be formed by subtractive manufacturing processes such as milling.

In step <NUM>, a plurality of bump foil pad segments (such as bump foil pad segments <NUM>, shown in <FIG>) are manufactured. Each bump foil pad segment can include a plurality of foil bumps which varies in stiffness along a length of the bump foil pad segment. The bump foil pad segments can be formed out of a sheet of a sheet metal and can be shaped with a die to form the plurality of foil bumps.

In step <NUM>, a plurality of top foil pad segments (such as top foil pad segments <NUM>, shown in <FIG>) are manufactured. The top foil pad segments can be formed out of a sheet metal.

In step <NUM>, the bump foil pad segments are assembled into a bump foil (such as bump foil <NUM>, shown in <FIG>). The bump foil can extend about a central bump foil cavity (such as central bump foil cavity <NUM>, shown in <FIG>) from a first open end (such as first open end <NUM> of bump foil <NUM>, shown in <FIG>) to a second open end (such as second open end <NUM> of bump foil <NUM>, shown in <FIG>) and can have a tapered shape such that the diameter of the first open end of the bump foil is greater than the diameter of the second open end of the bump foil.

In step <NUM>, the top foil pad segments are assembled into a top foil (such as top foil <NUM>, shown in <FIG>). The top foil can extend about a central top foil cavity (such as central top foil cavity <NUM>, shown in <FIG>) from a first open end (such as first open end <NUM> of top foil <NUM>, shown in <FIG>) to a second open end (such as second open end <NUM> of top foil <NUM>, shown in <FIG>) and can have a tapered shape such that the diameter of the first open end of the top foil is greater than the diameter of the second open end of the top foil.

In step <NUM>, the bump foil is inserted into the central bearing sleeve cavity through the first open end of the bearing sleeve. In some examples, one or more protruding sections of the bump foil can slide into a corresponding section on the interior surface of the bearing sleeve (such as support dovetails and/or support slots).

In step <NUM>, the top foil is inserted into the central bump foil cavity through the first open end of the bump foil. In some examples, one or more protruding sections of the top foil can slide into a corresponding section on the interior surface of the bearing sleeve (such as support dovetails and/or support slots).

<FIG> is a perspective view of an inner end of conical bearing <NUM> about shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM> (shown in <FIG>). Conical bearing <NUM> extends from inner end <NUM> to outer end <NUM> and includes exterior surface <NUM> and interior surface <NUM> (shown in <FIG>). In the example shown in <FIG>, bearing sleeve <NUM> includes cooling channels <NUM>. Bump foil <NUM> includes foil bumps <NUM> (shown in <FIG>). <FIG> is a cross-sectional view of conical bearing <NUM> along plane A (shown in <FIG>). <FIG> is a cross-sectional view of a portion of conical bearing <NUM> along plane B (shown in <FIG>). <FIG> will be discussed concurrently below.

Conical bearing <NUM> can operate in substantially the same manner as conical bearing <NUM> (described above in reference to <FIG> and <FIG>) with respect to the support of shaft <NUM> during rotation.

As shown in <FIG> and <FIG>, bump foil <NUM> can have a varying geometry along its circumference in order to vary the stiffness of bump foil <NUM>. This can be achieved by, for example, varying the bump height and/or bump pitch of bump foil <NUM> along its circumference (as described above in reference to <FIG>). As described above in reference to <FIG>, the loads exerted by shaft <NUM> vary based on the rotational position of shaft <NUM>. The stiffness of bump foil <NUM> can be varied to distribute the expected loads exerted by shaft <NUM> at different rotational positions. As shown in <FIG>, the radius of bearing sleeve <NUM> can also be varied along the circumference of bearing sleeve <NUM> to accommodate the differing dimensions of bump foil <NUM> and the expected movement of shaft <NUM> during rotation. For example, radius R<NUM> of bearing sleeve <NUM> (aligning with an area of greater bump height and lesser bump pitch within bump foil <NUM>) is less than radius R<NUM> (aligning with an area of lesser bump height and greater bump pitch within bump foil <NUM>, as well as with the location of maximum pre-load on the bearing). The varying radius of bearing sleeve <NUM> can result in a non-circular profile of the interior surface of bearing sleeve <NUM>. This varying radius of bearing sleeve <NUM> is shown in <FIG> (also shown in <FIG> and <FIG>), and can assist in generation of hydrodynamic pressure from the leading edge of each bump foil pad section to the trailing edge.

As shown in <FIG>, shaft <NUM> exerts force on conical bearing <NUM> as shaft <NUM> rotates. Shaft <NUM> exerts radial force on conical bearing <NUM> along direction Fradial and exerts axial force on conical bearing <NUM> along direction Faxial. As the loads exerted by shaft <NUM> vary based on the rotational position of shaft <NUM>, conical bearing <NUM> can distribute the varying loads exerted by shaft <NUM> through the variable stiffness of bump foil <NUM>.

As shown in <FIG>, bump foil <NUM> can include a plurality of foil bumps <NUM>. Each foil bump <NUM> has a bump height H and a bump pitch p. Foil bumps <NUM> can vary in height and/or pitch along the circumference of bump foil <NUM> in order to vary the stiffness of bump foil <NUM>. As described above in reference to <FIG>, the loads exerted by shaft <NUM> vary based on the rotational position of shaft <NUM>. The stiffness of bump foil <NUM> can be tailored at different points to achieve the necessary load distribution.

<FIG> is a cross-sectional view of a portion of conical bearing <NUM> and a portion of shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM>. Conical bearing <NUM> extends from an inner end (not shown in <FIG>) to an outer end (not shown in <FIG>). Bearing sleeve <NUM> includes cooling channel <NUM> and support slot <NUM>. Bump foil <NUM> includes bump foil leading edge <NUM>, bump foil trailing edge <NUM>, and foil bumps <NUM>. Top foil <NUM> includes top foil leading edge <NUM> and top foil trailing edge <NUM>.

Bump foil leading edge <NUM> and top foil leading edge <NUM> can extend radially outward from the center of bump foil <NUM> and top foil <NUM>, respectively. Support slot <NUM> can be shaped to match the geometry (for example, the length and angle) of bump foil leading edge <NUM> and top foil leading edge <NUM>. In the example shown in <FIG>, support slot <NUM> is a slot which extends radially outward from the center of bearing sleeve <NUM> and which extends axially along bearing sleeve <NUM> in the same manner as cooling channel <NUM>. When conical bearing <NUM> is assembled, bump foil leading edge <NUM> and top foil leading edge <NUM> can be slidably inserted into support slot <NUM> to secure the respective bump foil or top foil pad segment within bearing sleeve <NUM>. Additionally, support slot <NUM> can secure bump foil leading edge <NUM> and top foil leading edge <NUM> during rotation of shaft <NUM> by pinning the foils in place at their respective leading edges. In designs including one or more support slots <NUM>, bump foil trailing edge <NUM> and top foil trailing edge <NUM> are left free. In examples where each of bump foil <NUM> and top foil <NUM> include three pad sections extending circumferentially about the foil, bearing sleeve <NUM> can include three support slots <NUM>.

<FIG> is a cross-sectional view of a portion of conical bearing <NUM> and a portion of shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM>. Conical bearing <NUM> extends from an inner end (not shown in <FIG>) to an outer end (not shown in <FIG>). Bearing sleeve <NUM> includes cooling channel <NUM> and support dovetail <NUM>. Bump foil <NUM> includes bump foil leading edge <NUM>, bump foil trailing edge <NUM>, and foil bumps <NUM>. Top foil <NUM> includes top foil leading edge <NUM> and top foil trailing edge <NUM>. Support dovetail <NUM> can include leading edge side <NUM> and trailing edge side <NUM>.

Top foil leading edge <NUM> and top foil trailing edge <NUM> can each have a stepped shape. In this manner, a portion of both top foil leading edge <NUM> and top foil trailing edge <NUM> can extend radially outward from the center of top foil <NUM>. A radially outermost portion of both top foil leading edge <NUM> and top foil trailing edge <NUM> can extend circumferentially from the radially extending portions, in the same manner as the rest of top foil <NUM>. Support dovetail <NUM> can extend radially inward toward the center of bearing sleeve <NUM> and can be shaped to match the geometry (for example, the length, shape, and angle) of top foil leading edge <NUM> and top foil trailing edge <NUM>. In the example shown in <FIG>, support dovetail <NUM> includes two recessed areas (leading edge side <NUM> and trailing edge side <NUM>) to receive the corresponding geometry of bump foil <NUM> and top foil <NUM>. When conical bearing <NUM> is assembled, top foil leading edge <NUM> can be slidably inserted into leading edge side <NUM> of support dovetail <NUM> to secure the leading edge of the respective top foil pad segment within bearing sleeve <NUM>. Similarly, top foil trailing edge <NUM> can be slidably inserted into trailing edge side <NUM> of support dovetail <NUM> to secure the trailing edge of the respective top foil pad segment within bearing sleeve <NUM>. Additionally, support dovetail <NUM> can secure bump foil leading edge <NUM> and top foil leading edge <NUM> during rotation of shaft <NUM> by retaining the foils in place at their respective leading edges. Similarly, support dovetail <NUM> can secure bump foil trailing edge <NUM> and top foil trailing edge <NUM> during rotation of shaft <NUM> by retaining the foils in place at their respective trailing edges. In this manner, in designs including one or more support dovetails <NUM>, bump foil leading edge <NUM>, bump foil trailing edge <NUM>, top foil leading edge <NUM>, and top foil trailing edge <NUM> are secured by the geometry of support dovetail(s) <NUM>. In examples where each of bump foil <NUM> and top foil <NUM> include three pad sections extending circumferentially about the foil, bearing sleeve <NUM> can include three support dovetails <NUM> which align with the end of each pad section.

<FIG> is a perspective view of conical bearing <NUM> oriented about shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM>. Conical bearing <NUM> extends from inner end <NUM> to outer end <NUM>. In the example shown in <FIG>, bearing sleeve <NUM> includes cooling channels <NUM> and anti-rotation tabs <NUM>. <FIG> is a side view of conical bearing <NUM> at inner end <NUM>. <FIG> will be discussed concurrently.

Conical bearing <NUM> can be made in substantially the same way, and operate in substantially the same manner with respect to the support of shaft <NUM> during rotation, as conical bearing <NUM> (described above in reference to <FIG>).

Bearing sleeve <NUM> can include one or more anti-rotation tabs <NUM>. Anti-rotation tabs <NUM> can be built with bearing sleeve <NUM> during the additive manufacturing build process, such that bearing sleeve <NUM> is a monolithic structure. Alternatively, anti-rotation tabs <NUM> can be built separately, and bearing sleeve <NUM> can be assembled after construction. Anti-rotation tabs <NUM> help to prevent rotation of bearing sleeve <NUM> during operation (that is, during rotation of shaft <NUM>). In some examples, anti-rotation tabs <NUM> can be fitted against corresponding holes within the support housings (not shown) for conical bearing <NUM>. This can help limit the rotation of bearing sleeve <NUM> within the support housing if shaft <NUM> were to catch against bearing sleeve <NUM>.

<FIG> is a perspective view of conical bearing <NUM> oriented about shaft <NUM>. Conical bearing <NUM> includes bearing sleeve <NUM>, bump foil <NUM>, and top foil <NUM> (shown in <FIG>). Conical bearing <NUM> extends from inner end <NUM> to outer end <NUM>. In the example shown in <FIG>, conical bearing includes cooling channels <NUM> and cooling holes <NUM>. <FIG> is a top plan view of a portion of bearing sleeve <NUM> including cooling channel <NUM> and cooling holes <NUM>. <FIG> is an interior perspective view of conical bearing <NUM>, including bearing sleeve <NUM>, bump foil <NUM>, top foil <NUM>, cooling holes <NUM>, foil bumps <NUM>, and support dovetail <NUM>. <FIG> will be discussed concurrently.

Cooling channels <NUM> can extend axially along the exterior surface of bearing sleeve <NUM>. In examples of conical bearing <NUM> which include foil geometry support features (such as support dovetail <NUM> shown in <FIG>), a cooling channel <NUM> can be located radially outward from the support feature. Each cooling hole <NUM> can extend from an exterior end <NUM> (shown in <FIG>) to an interior end <NUM> (shown in <FIG>). Exterior ends <NUM> of cooling holes <NUM> can be situated within a cooling channel <NUM>, and cooling holes <NUM> can extend radially inward through bearing sleeve <NUM> toward bump foil <NUM> and top foil <NUM>. In examples of conical bearing <NUM> which include foil geometry support features (such as support dovetail <NUM>), cooling holes <NUM> can extend through the support feature such that interior ends <NUM> are adjacent to an interior cavity of conical bearing <NUM>.

Cooling channels <NUM> and cooling holes <NUM> can facilitate cooling flow about shaft <NUM>. High pressure air, or another fluid, can be directed along the exterior of bearing sleeve <NUM> along cooling channels <NUM>, and additionally or alternatively can be injected into conical bearing <NUM> to enable hybridization of the bearing by combining hydrodynamic and hydrostatic bearing for improved load capacity. Conical bearing <NUM> can utilize both hydrodynamic and hydrostatic air to more efficiently cool both conical bearing <NUM> and shaft <NUM>, and provide increased air film stiffness to support high dynamic loads. Cooling channels <NUM> can provide air flow passages to dissipate heat from conical bearing <NUM> via forced convection. Cooling holes <NUM> can supply additional cooling flow to conical bearing <NUM> via radial injection using a process fluid. Additionally or alternatively, a high pressure process fluid can be drawn into cooling holes <NUM> from an external source, such as compressor bleed air. This provides hydrostatic air to increase air film stiffness and improve bearing load capacity. Cooling holes <NUM> thus act as a control orifice to regulate bearing supply pressure hydrostatically.

It should be understood that any of the features described above in reference to <FIG> can be combined into a single conical bearing. For example, a single conical bearing can incorporate any combination of axial splits in the bump foil and/or top foil, pad segments forming the bump foil and/or top foil, varying bump height, varying bump pitch, one or more support slots, one or more support dovetails, one or more anti-rotation tabs, cooling channels, and cooling holes.

A conical bearing as described herein provides numerous advantages. Integrating the axial and radial support elements removes the need for shimming and allows for the elimination of thrust bearings in the bearing system. This reduces the mass and complexity of rotor assemblies, and further can reduce the possible points of failure within the bearing system. Additionally, varying bump foil stiffness achieved through the variation of bump height and/or bump pitch accounts for changes in the direction of the loads exerted by the shaft. The conical bearing designs described herein are scalable and can be suitable for aerospace or non-aerospace applications. Axially split foil components can reduce global deformation of the bearing assembly by allowing each of the split components to locally deform independently of each other. The bearing sleeve of the conical bearing can be additively manufactured to include features such as support slots or dovetails to retain the foil ends, anti-rotation tabs, cooling channels, and/or cooling holes, which can further improve the reliability and performance of the conical bearing. Finally, the cooling components can enable hybrid (both hydrodynamic and hydrostatic) cooling of the bearing (that is, axially along the bearing, as well as through the cooling holes within the cooling channels).

Claim 1:
A conical bearing (<NUM>; <NUM>; <NUM>; <NUM>; <NUM><NUM>) comprising:
a bearing sleeve (<NUM>; <NUM>) extending along an axis from a first open end (<NUM>) to a second open end (<NUM>), and having an axially tapered shape such that a first open end diameter of the bearing sleeve (<NUM>; <NUM>) is greater than a second open end diameter of the bearing sleeve (<NUM>; <NUM>);
a bump foil (<NUM>; <NUM>) concentrically disposed within the bearing sleeve (<NUM>; <NUM>) with respect to the axis and comprising a plurality of bump foil pad segments (<NUM>) extending circumferentially about an interior surface (<NUM>) of the bearing sleeve (<NUM>; <NUM>), wherein each bump foil pad segment (<NUM>) comprises a plurality of foil bumps (<NUM>); and
a top foil (<NUM>; <NUM>) concentrically disposed within the bump foil (<NUM>; <NUM>) with respect to the axis and comprising a plurality of top foil pad segments (<NUM>) extending circumferentially about an interior surface (<NUM>) of the bump foil (<NUM>; <NUM>),
wherein the conical bearing is characterised by:
the interior surface (<NUM>) of the bearing sleeve (<NUM>; <NUM>) having a non-circular profile; and
the plurality of foil bumps (<NUM>; <NUM>; <NUM>; <NUM>) varying in stiffness along a circumference of the bump foil (<NUM>; <NUM>).