Patent Description:
A gas turbine engine may include an electric machine for providing mechanical power and/or electricity. The electric machine is typically connected to a gearbox outside of a core of the engine, where the gearbox is coupled with a rotor within the engine core via a tower shaft. Some efforts have been made to arrange the electric machine within the engine core to reduce overall size of the gas turbine engine. There is a need in the art, however, for structures and components which facilitate arrangement of the electric machine within the engine core. In particular, there is a need in the art for structures and components which facilitate coupling a rotating component of the electric machine or a gearbox for the electric machine with a turbine engine shaft.

Prior art includes <CIT>, <CIT>, <CIT> and <CIT>.

According to an aspect of the present invention, an assembly is provided for a turbine engine as claimed in claim <NUM>.

Embodiments of this aspect of the invention are provided in claims dependent from claim <NUM>.

<FIG> illustrates an assembly <NUM> for a turbine engine. This turbine engine assembly <NUM> includes a rotating structure <NUM>, a stationary structure <NUM> and at least one rotating structure bearing <NUM> that rotatably mounts the rotating structure <NUM> to the stationary structure <NUM>. The turbine engine assembly <NUM> also includes a turbine engine apparatus <NUM> (e.g., a removable and/or self-contained module) and a component coupler <NUM> (e.g., a double splined coupler, a double articulation quill shaft) that couples the rotating structure <NUM> with a component of the turbine engine apparatus <NUM>.

The rotating structure <NUM> extends axially along a rotational axis <NUM> to a distal end <NUM> of the rotating structure <NUM>, which rotational axis <NUM> may be an axial centerline of the turbine engine assembly <NUM>. The rotating structure <NUM> extends circumferentially around and is rotatable about the rotational axis <NUM>. The rotating structure <NUM> may be configured as or otherwise include any rotatable component or assembly of rotatable components within the turbine engine. The rotating structure <NUM> of <FIG>, for example, is configured as a turbine engine shaft <NUM>. However, this rotating structure <NUM> may also include one or more additional elements such as, but not limited to, sleeves, spacers, rotors, seal elements, etc. Furthermore, while the turbine engine shaft <NUM> may be configured as a single monolithic body, the turbine engine shaft <NUM> may alternatively include a plurality of interconnected shafts / shaft segments.

The stationary structure <NUM> may be configured as or otherwise include any stationary (e.g., static, non-rotating) component or assembly of stationary components within the turbine engine. The stationary structure <NUM>, for example, may include a turbine engine case and one or more internal support structures within and connected to the turbine engine case.

The structure bearing <NUM> may be configured as a rolling element bearing. The structure bearing <NUM> of <FIG>, for example, includes a bearing inner race <NUM>, a bearing outer race <NUM> and a plurality of bearing rolling elements <NUM>. The inner race <NUM> is connected (e.g., fixedly mounted) to the rotating structure <NUM> and its turbine engine shaft <NUM>. The outer race <NUM> is connected (e.g., fixedly mounted) to the stationary structure <NUM>. The rolling elements <NUM> are arranged circumferentially about the rotational axis <NUM> in an array. The rolling elements <NUM> are disposed radially between and engaged with the inner race <NUM> and the outer race <NUM>. With this arrangement, the structure bearing <NUM> is configured to rotatably mount the rotating structure <NUM> and its turbine engine shaft <NUM> to the stationary structure <NUM>.

The turbine engine apparatus <NUM> may be configured as an electric machine system. The turbine engine apparatus <NUM> of <FIG>, for example, includes an electric machine <NUM> and a gearbox <NUM>.

The electric machine <NUM> is configurable as an electric motor and/or an electric generator. For example, during a motor mode of operation, the electric machine <NUM> may operate as the electric motor to convert electricity (e.g., received from a battery and/or another electricity source) into mechanical power; e.g., torque. This mechanical power may be utilized for various purposes within the turbine engine such as, for example, rotating the rotating structure <NUM> during turbine engine startup. During a generator mode of operation, the electric machine <NUM> may operate as the electric generator to convert mechanical power (e.g., received through the rotating structure <NUM>) into electricity. This electricity may be utilized for various purposes within the turbine engine such as, for example, electrically powering one or more electric components of the turbine engine and/or charging the battery. The electricity may also or alternatively be utilized for various purposes outside of the turbine engine such as, for example, electrically powering one or more electrical components in an aircraft.

The electric machine <NUM> includes an (e.g., annular) electric machine rotor <NUM> and an (e.g., annular) electric machine stator <NUM>. The electric machine <NUM> also includes an electric machine case <NUM> that at least partially or completely houses and/or supports the machine rotor <NUM> and/or the machine stator <NUM>. The machine rotor <NUM> is configured to move relative to (e.g., rotate within or about) the machine stator <NUM> to convert electricity into mechanical power or convert mechanical power into electricity depending upon the mode of electric machine operation. The machine rotor <NUM>, for example, may be rotatably mounted within the electric machine <NUM> to a stationary portion of the electric machine <NUM> (e.g., the machine case <NUM> and/or the machine stator <NUM>) via one or more internal electric machine bearings <NUM>; e.g., rolling element bearings. The machine stator <NUM> is connected (e.g., fixedly mounted) to the machine case <NUM>, and the machine case <NUM> is connected (e.g., fixedly mounted) to the stationary structure <NUM>.

The gearbox <NUM> of <FIG> includes a gearbox first gear <NUM> (e.g., a sun gear), a gearbox second gear <NUM> (e.g., a sun gear) and one or more gearbox idlers <NUM> (see also <FIG>) (e.g., star gear-shafts), which gearbox idlers <NUM> are distributed circumferentially about the rotational axis <NUM> in an array. The gearbox <NUM> of <FIG> also includes a gearbox case <NUM> that at least partially or completely houses and/or supports one or more of the gearbox elements <NUM>-<NUM>.

The gearbox first gear <NUM> and the gearbox second gear <NUM> are rotatable about the rotational axis <NUM>. The gearbox first gear <NUM> is axially spaced from the gearbox second gear <NUM> along the rotational axis <NUM>.

Each of the gearbox idlers <NUM> of <FIG> includes an idler base <NUM> (e.g., a shaft), an idler first gear <NUM> (e.g., a star gear) and an idler second gear <NUM> (e.g., a star gear). Each gearbox idler <NUM> and its base <NUM> are rotatably mounted to the gearbox case <NUM> by one or more internal gearbox bearings <NUM>; e.g., rolling element bearings. Each gearbox idler <NUM> and its base <NUM> of <FIG> are rotatable about an idler (e.g., gear-shaft) rotational axis <NUM> of the gearbox idler <NUM> (e.g., gear-shaft), which rotational axis <NUM> is parallel with and radially offset from the rotational axis <NUM>. The first gear <NUM> and the second gear <NUM> are connected to the base <NUM>. The first gear <NUM> is axially spaced from the second gear <NUM> along the rotational axis <NUM>.

The first gear <NUM> is mated with the gearbox first gear <NUM>. More particularly, exterior gear teeth of the first gear <NUM> are meshed with exterior gear teeth of the gearbox first gear <NUM>. Similarly, the idler second gear <NUM> is mated with the gearbox second gear <NUM>. More particularly, exterior gear teeth of the second gear <NUM> are meshed with exterior gear teeth of the gearbox second gear <NUM>. Each gearbox idler <NUM> (e.g., gear-shaft) thereby couples and transmits torque between the gearbox first gear <NUM> and the gearbox second gear <NUM>, where the gearbox second gear <NUM> of <FIG> is coupled to the electric machine <NUM> and its machine rotor <NUM> by an inter-gearbox-machine coupler <NUM>.

The gearbox <NUM> of <FIG> is configured as a speed change device between the rotating structure <NUM> and the electric machine <NUM> and its machine rotor <NUM>. For example, the gearbox first gear <NUM> is configured with an outer diameter that is different (e.g., greater) than an outer diameter of the gearbox second gear <NUM>. The first gear <NUM> is also (or alternatively) configured with an outer diameter that is different (e.g., less) than an outer diameter of the second gear <NUM>. With this arrangement, the gearbox <NUM> of <FIG> may be configured as a speed change device. The gearbox <NUM> of <FIG>, for example, may be configured as a speed reduction device when, for example, the electric machine <NUM> and its machine rotor <NUM> drive the rotating structure <NUM>. However, in other embodiments, the gearbox elements <NUM>-<NUM> may alternatively be configured such that the gearbox <NUM> is a speed reduction device as the rotating structure <NUM> drives the electric machine <NUM> and its machine rotor <NUM>.

The component coupler <NUM> extends axially along the rotational axis <NUM> between and to a first end <NUM> of the component coupler <NUM> and a second end <NUM> of the component coupler <NUM>. The component coupler <NUM> is rotatable about the rotational axis <NUM>. The component coupler <NUM> is coupled to the rotating structure <NUM> and its turbine engine shaft <NUM> by a compliant coupler-shaft connection <NUM> at (e.g., on, adjacent or proximate) the coupler first end <NUM>. The component coupler <NUM> is thereby configured to rotate with the rotating structure <NUM> and its turbine engine shaft <NUM> about the rotational axis <NUM>. The component coupler <NUM> is coupled to the gearbox <NUM> and its gearbox first gear <NUM> by a compliant coupler-gear connection <NUM> at the coupler second end <NUM>. The component coupler <NUM> is thereby configured to rotate with the gearbox first gear <NUM> about the rotational axis <NUM>.

The coupler-shaft connection <NUM> of <FIG> is configured as a crowned spline connection. The rotating structure <NUM> and its turbine engine shaft <NUM> of <FIG>, for example, includes a plurality of (e.g., internal) shaft splines <NUM> (e.g., ribs, teeth, etc.), and the component coupler <NUM> includes a plurality of (e.g., external) first coupler splines <NUM> (e.g., ribs, teeth, etc.) at the coupler first end <NUM> (see <FIG>). The shaft splines <NUM> are arranged circumferentially about the rotational axis <NUM> in an annular array, and the first coupler splines <NUM> are arranged circumferentially about the rotational axis <NUM> in an annular array. The shaft splines <NUM> are meshed with the first coupler splines <NUM>. The shaft splines <NUM> of <FIG>, for example, are interspersed with the first coupler splines <NUM>, and the first coupler splines <NUM> are interspersed with the shaft splines <NUM>. More particularly, each shaft spline <NUM> projects radially (e.g., inward) into a respective first coupler groove in the component coupler <NUM>, where the first coupler groove is formed by and circumferentially between a circumferentially neighboring (e.g., adjacent) pair of the first coupler splines <NUM>. Similarly, each of the first coupler splines <NUM> projects radially (e.g., outward) into a respective shaft groove in the rotating structure <NUM> and its turbine engine shaft <NUM>, where the shaft groove is formed by and circumferentially between a circumferentially neighboring pair of the shaft splines <NUM>. With this arrangement, the component coupler <NUM> may slightly move (e.g., axially translate) relative to the rotating structure <NUM> and its turbine engine shaft <NUM> during turbine engine operation.

The crowned spline connection <FIG> is configured as a single crowned spline connection where the first coupler splines <NUM> are crowned splines and the shaft splines <NUM> are non-crowned (e.g., rectangular, straight) splines. Each first coupler spline <NUM> of <FIG>, for example, has a convex (e.g., curved, arcuate, etc.) tip profile when viewed, for example, in a reference plane parallel with and/or coincident with the rotational axis <NUM> (see <FIG>). Each shaft spline <NUM> of <FIG>, by contrast, has a straight tip profile when viewed, for example, in the reference plane. In other embodiments however, referring to <FIG>, the shaft splines <NUM> may be crowned splines and the first coupler splines <NUM> may be non-crowned (e.g., rectangular, straight) splines. In still other embodiments, referring to <FIG>, the crowned spline connection may be configured as a double crowned spline connection where both the first coupler splines <NUM> and the shaft splines <NUM> are crowned splines. In addition to or as an alternative to the profiles of <FIG>, each of the splines <NUM> of <FIG> has a convex (e.g., curved, arcuate, etc.) flank side profile when viewed, for example, in a second reference plane parallel with and radially spaced from the rotational axis <NUM>. Each of the splines <NUM> of <FIG>, by contrast, may be configured with a straight flank side profile when viewed, for example, in the second reference plane. In another example, each of the splines <NUM> of <FIG> has a convex (e.g., curved, arcuate, etc.) flank side profile when viewed, for example, in the second reference plane. Each of the splines <NUM> of <FIG>, by contrast, may be configured with a straight flank side profile when viewed, for example, in the second reference plane.

The crowned spline connections of <FIG> may accommodate additional (e.g., more than just axial) movement between the component coupler <NUM> and the rotating structure <NUM> and its turbine engine shaft <NUM> of <FIG>. The crowned spline connections of <FIG>, for example, may accommodate slight axial mis-alignment (e.g., pivoting) between the component coupler <NUM> and the rotating structure <NUM> and its turbine engine shaft <NUM> of <FIG>.

The coupler-gear connection <NUM> of <FIG> is configured as a crowned spline connection. The gearbox first gear <NUM> of <FIG>, for example, includes a plurality of (e.g., internal) gear splines <NUM> (e.g., ribs, teeth, etc.), and the component coupler <NUM> includes a plurality of (e.g., external) second coupler splines <NUM> (e.g., ribs, teeth, etc.) at the coupler second end <NUM> of <FIG>. The gear splines <NUM> are arranged circumferentially about the rotational axis <NUM> in an annular array, and the second coupler splines <NUM> are arranged circumferentially about the rotational axis <NUM> in an annular array. The gear splines <NUM> are meshed with the second coupler splines <NUM>. The gear splines <NUM> of <FIG>, for example, are interspersed with the second coupler splines <NUM>, and the second coupler splines <NUM> are interspersed with the gear splines <NUM>. More particularly, each gear spline <NUM> projects radially (e.g., inward) into a respective second coupler groove in the component coupler <NUM>, where the second coupler groove is formed by and circumferentially between a circumferentially neighboring (e.g., adjacent) pair of the second coupler splines <NUM>. Similarly, each of the second coupler splines <NUM> projects radially (e.g., outward) into a respective gear groove in the gearbox first gear <NUM>, where the gear groove is formed by and circumferentially between a circumferentially neighboring pair of the gear splines <NUM>. With this arrangement, the component coupler <NUM> may slightly move (e.g., axially translate) relative to the gearbox first gear <NUM> during turbine engine operation.

The crowned spline connection <FIG> is configured as a single crowned spline connection where the second coupler splines <NUM> are crowned splines and the gear splines <NUM> are non-crowned (e.g., rectangular, straight) splines. Each second coupler spline <NUM> of <FIG>, for example, has a convex (e.g., curved, arcuate, etc.) tip profile when viewed, for example, in the reference plane. Each gear spline <NUM> of <FIG>, by contrast, has a straight tip profile when viewed, for example, in the reference plane. In other embodiments however, referring to <FIG>, the gear splines <NUM> may be crowned splines and the second coupler splines <NUM> may be non-crowned (e.g., rectangular, straight) splines. In still other embodiments, referring to <FIG>, the crowned spline connection may be configured as a double crowned spline connection where both the second coupler splines <NUM> and the gear splines <NUM> are crowned splines. In addition to or as an alternative to the profiles of <FIG>, each of the splines <NUM> of <FIG> has a convex (e.g., curved, arcuate, etc.) flank side profile when viewed, for example, in the second reference plane. Each of the splines <NUM> of <FIG>, by contrast, may be configured with a straight flank side profile when viewed, for example, in the second reference plane. In another example, each of the splines <NUM> of <FIG> has a convex (e.g., curved, arcuate, etc.) flank side profile when viewed, for example, in the second reference plane. Each of the splines <NUM> of <FIG>, by contrast, may be configured with a straight flank side profile when viewed, for example, in the second reference plane.

The crowned spline connections of <FIG> may accommodate additional (e.g., more than just axial) movement between the component coupler <NUM> and the gearbox first gear <NUM> of <FIG>. The crowned spline connections of <FIG>, for example, may accommodate slight axial mis-alignment (e.g., pivoting) between the component coupler <NUM> and the gearbox first gear <NUM> of <FIG>. The component coupler <NUM> of <FIG> may thereby accommodate various operational shifts between the rotating structure <NUM> and the turbine engine apparatus <NUM> during turbine engine operation where, for example, an axial centerline of the turbine engine shaft <NUM> may become momentarily angularly offset from an axial centerline of the gearbox <NUM>.

Referring to <FIG>, the component coupler <NUM> may be configured with a dumbbell configuration. The component coupler <NUM> of <FIG>, for example, includes a splined shaft <NUM> and a splined element <NUM> attached (e.g., removably mounted) to the splined shaft <NUM>.

The splined shaft <NUM> of <FIG> includes a shaft base <NUM> and a shaft rim <NUM>; e.g., an annular flange. The shaft base <NUM> extends axially along the rotational axis <NUM> between and to the coupler first end <NUM> and the coupler second end <NUM>. The shaft rim <NUM> is connected to the shaft base <NUM> and disposed at the coupler second end <NUM>. The shaft rim <NUM> projects radially out from the shaft base <NUM> to an outer periphery <NUM> of the shaft rim <NUM>. The shaft rim <NUM> includes / forms the second coupler splines <NUM>. These second coupler splines <NUM> are arranged circumferentially about the shaft rim <NUM> / the rotational axis <NUM> at the rim outer periphery <NUM>. The second coupler splines <NUM> of <FIG> thereby form the rim outer periphery <NUM> of the shaft rim <NUM>.

The shaft rim <NUM> and/or its second coupler splines <NUM> have a rim width <NUM> along the rotational axis <NUM>. The rim outer periphery <NUM> has a (e.g., maximum) rim radius <NUM> at, for example, an apex of the second coupler splines <NUM>.

The splined element <NUM> may be configured as an annular body. The splined element <NUM> of <FIG>, for example, extends axially along the rotational axis <NUM> between and to opposing sides <NUM> and <NUM> of the splined element <NUM>. The splined element <NUM> extends radially between and to an inner periphery of the splined element <NUM> and an outer periphery <NUM> of the splined element <NUM>. The splined element <NUM> extends circumferentially about (e.g., completely around) the rotational axis <NUM>.

The shaft base <NUM> of <FIG> projects axially through (or into) a bore of the splined element <NUM>. This splined element <NUM> may be rotationally fixed to the splined shaft <NUM> by a spline connection <NUM>; e.g., a straight-spline connection. The splined element <NUM> may be axially fixed to the splined shaft <NUM> by, for example, one or more retainers <NUM> and <NUM>; e.g., split rings. Each retainer <NUM>, <NUM>, for example, is disposed within a respective receptacle (e.g., groove, notch, etc.) in the shaft base <NUM> axially adjacent a respective side <NUM>, <NUM> of the splined element <NUM>.

When attached to the splined shaft <NUM> and its shaft base <NUM>, the splined element <NUM> projects radially out from the shaft base <NUM> to its element outer periphery <NUM>. The splined element <NUM> includes / forms the first coupler splines <NUM>. These first coupler splines <NUM> are arranged circumferentially about the splined element <NUM> / the rotational axis <NUM> at the element outer periphery <NUM>. The first coupler splines <NUM> of <FIG> thereby form the element outer periphery <NUM> of the splined element <NUM>.

The splined element <NUM> of <FIG> is spaced axially from the shaft rim <NUM>. The component coupler <NUM> is thereby configured with an annular channel <NUM>. This annular channel <NUM> project radially into the component coupler <NUM> to the shaft base <NUM>. The annular channel <NUM> extends axially along the rotational axis <NUM> within the component coupler <NUM> between and to the splined element <NUM> and the shaft rim <NUM>. The annular channel <NUM> extends circumferentially about (e.g., completely around) the rotational axis <NUM> through the component coupler <NUM>.

The splined element <NUM> and/or its first coupler splines <NUM> have an element width <NUM> along the rotational axis <NUM>. This element width <NUM> may be sized different (e.g., less) than the rim width <NUM>. The element outer periphery <NUM> has a (e.g., maximum) element radius <NUM> at, for example, an apex of the first coupler splines <NUM>. This element radius <NUM> may be sized different (e.g., greater) than the rim radius <NUM>. The present disclosure, however, is not limited to such an exemplary dimensional arrangement. For example, in other embodiments, the element width <NUM> may be equal to the rim width <NUM> and/or the element radius <NUM> may be equal to the rim radius <NUM>. Furthermore, while the splined element <NUM> is described above as including / forming the first coupler splines <NUM> and the splined shaft <NUM> is described as including / forming the second coupler splines <NUM>, the component coupler <NUM> may be reoriented in other embodiments such that the splined element <NUM> includes / forms the second coupler splines <NUM> and the splined shaft <NUM> includes / forms the first coupler splines <NUM>.

In some embodiments, referring to <FIG>, the component coupler <NUM> may be configured with a flexible coupling <NUM>; e.g., a flex mount. The shaft base <NUM> of <FIG>, for example, includes a first section <NUM> of the shaft base <NUM>, a second section <NUM> of the shaft base <NUM> and the flexible coupling <NUM>. The base first section <NUM> extends axially to the coupler first end <NUM> and is coupled to the splined element <NUM>. The base second section <NUM> extends axially to the coupler second end <NUM> is connected to the shaft rim <NUM>.

The flexible coupling <NUM> of <FIG> is configured to provide a flexible connection between the base first section <NUM> and the base second section <NUM>. The flexible coupling <NUM> of <FIG>, for example, is arranged between and connects the base first section <NUM> and base second section <NUM>. This flexible coupling <NUM> includes a first diaphragm <NUM>, a second diaphragm <NUM> and a bridge <NUM>. The first diaphragm <NUM> is connected to the base first section <NUM> and the bridge <NUM>. This first diaphragm <NUM> extends radially outward (or inward) from the base first section <NUM> to the bridge <NUM>. The second diaphragm <NUM> is connected to the base second section <NUM> and the bridge <NUM>. This second diaphragm <NUM> extends radially outward (or inward) from the base second section <NUM> to the bridge <NUM>. The bridge <NUM> extends axially along the rotational axis <NUM> between and to the first diaphragm <NUM> and the second diaphragm <NUM>. With this arrangement, the first diaphragm <NUM> and/or the second diaphragm <NUM> may facilitate slight axial shifts and/or slight pivoting between the base first section <NUM> and the base second section <NUM>. The flexible coupling <NUM> may thereby accommodate further operational shifts between the gearbox <NUM> and the turbine engine shaft <NUM> of <FIG>.

In some embodiments, referring to <FIG>, the turbine engine assembly <NUM> may also include a seal assembly <NUM> configured to seal an annular gap between the component coupler <NUM> and the stationary structure <NUM>, or alternatively another component connected to the stationary structure <NUM> such as, but not limited to, the gearbox case <NUM>. The seal assembly <NUM> may thereby fluidly isolate a first compartment <NUM> (e.g., a bearing compartment) within the turbine engine from a second compartment <NUM> (e.g., a gearbox compartment) within the turbine engine and, for example, its gearbox <NUM>.

The seal assembly <NUM> of <FIG> includes an annular seal land <NUM> and an annular seal element <NUM>; e.g., a carbon seal element. The seal land <NUM> is connected (e.g., removably mounted) to the component coupler <NUM>. The seal land <NUM> of <FIG>, for example, is mounted to and circumscribes a shelf portion <NUM> of the shaft base <NUM> axially adjacent the shaft rim <NUM>. This seal land <NUM> may be clamped onto the splined shaft <NUM> using a nut <NUM>. The seal land <NUM> and the nut <NUM> may be installed with and removed from the splined shaft <NUM> where the splined element <NUM> of <FIG> is removed from / uninstalled with the splined shaft <NUM>.

The seal element <NUM> of <FIG> is connected (e.g., spring mounted) to the stationary structure <NUM> or the gearbox case <NUM> via a biasing device <NUM>; e.g., a spring. The biasing device <NUM> is configured to bias (e.g., push) the seal element <NUM> against the seal land <NUM> to maintain sealing engagement between the seal assembly components <NUM> and <NUM>.

<FIG> illustrates an example of the turbine engine with which the turbine engine assembly <NUM> may be configured. This turbine engine is configured as a geared, turbofan gas turbine engine <NUM>. This turbine engine <NUM> extends along the rotational axis <NUM> between an upstream airflow inlet <NUM> and a downstream airflow exhaust <NUM>. The turbine engine <NUM> includes a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The compressor section <NUM> includes a low pressure compressor (LPC) section 147A and a high pressure compressor (HPC) section 147B. The turbine section <NUM> includes a high pressure turbine (HPT) section 149A and a low pressure turbine (LPT) section 149B.

The engine sections <NUM>-149B are arranged sequentially along the rotational axis <NUM> within an engine housing <NUM>. This engine housing <NUM> includes an inner case <NUM> (e.g., a core case) and an outer case <NUM> (e.g., a fan case). The inner case <NUM> may house one or more of the engine sections 147A-149B (e.g., an engine core) as well as the turbine engine apparatus <NUM>. The outer case <NUM> may house at least the fan section <NUM>.

Each of the engine sections <NUM>, 147A, 147B, 149A and 149B includes a respective bladed rotor <NUM>-<NUM>. Each of these bladed rotors <NUM>-<NUM> includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The fan rotor <NUM> is connected to a gear train <NUM>, for example, through a fan shaft <NUM>. The gear train <NUM> and the LPC rotor <NUM> are connected to and driven by the LPT rotor <NUM> through a low speed shaft <NUM>. The HPC rotor <NUM> is connected to and driven by the HPT rotor <NUM> through a high speed shaft <NUM>. The shafts <NUM>-<NUM> are rotatably supported by a plurality of bearings <NUM>; e.g., rolling element bearings. Each of these bearings <NUM> is connected to the engine housing <NUM> by, for example, an annular support strut.

During operation, air enters the turbine engine <NUM> through the airflow inlet <NUM>. This air is directed through the fan section <NUM> and into a core flowpath <NUM> and a bypass flowpath <NUM>. The core flowpath <NUM> extends sequentially through the engine sections 147A-149B. The air within the core flowpath <NUM> may be referred to as "core air". The bypass flowpath <NUM> extends through a bypass duct, which bypasses the engine core. The air within the bypass flowpath <NUM> may be referred to as "bypass air".

The core air is compressed by the LPC rotor <NUM> and the HPC rotor <NUM> and directed into a combustion chamber <NUM> of a combustor in the combustor section <NUM>. This fuel air mixture is ignited and combustion products thereof flow through and sequentially cause the HPT rotor <NUM> and the LPT rotor <NUM> to rotate. The rotation of the HPT rotor <NUM> and the LPT rotor <NUM> respectively drive rotation of the HPC rotor <NUM> and the LPC rotor <NUM> and, thus, compression of the air received from a core airflow inlet. The rotation of the LPT rotor <NUM> also drives rotation of the fan rotor <NUM>, which propels bypass air through and out of the bypass flowpath <NUM>. The turbine engine of the present disclosure, however, is not limited to the foregoing exemplary thrust ratio.

The turbine engine assembly <NUM> may be configured at various different locations within the turbine engine <NUM>. For example, the turbine engine assembly <NUM> and its turbine engine apparatus <NUM> may be housed within the engine housing <NUM> and, more particularly, the inner case <NUM>. The stationary structure <NUM>, for example, may be or otherwise include the inner case <NUM>. The turbine engine apparatus <NUM> may also be disposed radially inboard of the core flowpath <NUM>, where the core flowpath <NUM> axially overlaps and extends circumferentially about (e.g., completely around, circumscribes) the turbine engine apparatus <NUM>. For example, the turbine engine apparatus <NUM> may be arranged with / axially aligned with the turbine section <NUM>, where the turbine engine shaft <NUM> may be one of the shafts <NUM>-<NUM> (e.g., <NUM>) and the structure bearing <NUM> may be a respective one of the bearings <NUM> supporting the respective shaft. The present disclosure, however, is not limited to such an exemplary arrangement. For example, in other embodiments, the turbine engine assembly <NUM> and its turbine engine apparatus <NUM> may also or alternatively be arranged with / aligned with another one or more sections <NUM>, <NUM> and/or <NUM> of the turbine engine <NUM>.

The gearbox <NUM> of <FIG> is described above as being paired with the electric machine <NUM>. However, in other embodiments, the electric machine <NUM> may be omitted (or arranged discrete from the gearbox <NUM>) and the gearbox <NUM> may be coupled with one or more other rotating components / structures within the turbine engine <NUM> of <FIG>. For example, the gearbox <NUM> may alternatively be configured as the gear train <NUM>.

The turbine engine assembly <NUM> may be included in various turbine engines other than the one described above. The turbine engine assembly <NUM>, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section, a compressor section and/or any other engine section. Alternatively, the turbine engine assembly <NUM> may be included in a direct drive turbine engine configured without a gear train. The turbine engine assembly <NUM> may be included in a turbine engine configured with a single spool, with two spools (e.g., see <FIG>), or with more than two spools. The turbine engine may be configured as a turbofan engine, a turbojet engine, a turboprop engine, a turboshaft engine, a propfan engine, a pusher fan engine or any other type of turbine engine. The turbine engine may alternatively be configured as an auxiliary power unit (APU) or an industrial gas turbine engine. The present disclosure therefore is not limited to any particular types or configurations of turbine engines.

Claim 1:
An assembly (<NUM>) for a turbine engine (<NUM>), comprising:
a turbine engine shaft (<NUM>) configured to rotate about a rotational axis (<NUM>);
a gearbox (<NUM>) comprising a gear (<NUM>, <NUM>) configured to rotate about the rotational axis (<NUM>); and
a coupler (<NUM>) coupled to the turbine engine shaft (<NUM>) by a coupler-shaft connection (<NUM>), the coupler-shaft connection (<NUM>) comprising a crowned spline connection, and the coupler (<NUM>) coupled to the gear (<NUM>) by a coupler-gear connection (<NUM>), and the coupler-gear connection (<NUM>) comprising a crowned spline connection,
characterised in that:
the coupler (<NUM>) includes a splined shaft (<NUM>) and a splined element (<NUM>) attached to the splined shaft (<NUM>);
the splined shaft (<NUM>) is coupled to the gear (<NUM>) by the coupler-gear connection (<NUM>);
the splined element (<NUM>) is coupled to the turbine engine shaft (<NUM>) by the coupler-shaft connection (<NUM>);
the splined shaft (<NUM>) comprises a base (<NUM>) and a rim (<NUM>) that projects radially out from and circumscribes the base (<NUM>);
the rim (<NUM>) is coupled to the gear (<NUM>) by the coupler-gear connection (<NUM>); and
the base (<NUM>) projects through a bore of the splined element (<NUM>).