Electric machine for integration into a propulsion engine

Abstract

An electric machine includes a stator assembly (302) coupled to a stator component of a propulsion engine (100). The stator assembly includes a stator support assembly (308) fixedly attached to the engine stator component and a stator (314) disposed on the stator support structure. A machine shaft (502) is coupled to an end of the shaft of the propulsion engine via an intermediate shaft member axially extending between an end of the shaft and the machine shaft. A bearing support frame (514) extends from the propulsion engine, and the bearing support frame and the machine shaft define a bearing cavity (520) therebetween. Machine bearings (522, 524) extend radially from the bearing support frame to rotatably contact the machine shaft. A rotor (346) is attached to a rotor support structure, and the rotor support structure is attached to the machine shaft. The rotor rotates with the machine shaft to exchange energy with the shaft of the propulsion engine.

Description

Technical Field

[0001] This specification generally relates to an electric machine for incorporation into a gas turbine engine. Background Art

[0002] Incorporating an electric machine (e.g., a generator) into a propulsion engine to generate electrical power from the mechanical energy generated by the propulsion engine can enhance the capabilities of an aircraft by eliminating the need for bulky energy storage devices on the aircraft. For example, the electrical power generated by the electric machine can be used to operate auxiliary thrusters (e.g., a fan, a motor, etc.) to supplement the thrust provided via the turbine engine. However, the introduction of such an electric machine may pose challenges related to size, weight, accessibility, and aerodynamic performance. Summary of the Invention

[0003] An electric machine includes a stator assembly coupled to an engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component and a stator disposed on a support surface of the stator support structure. The electric machine further includes a rotor assembly that includes a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator. The rotor exchanges rotational energy with the shaft to operate as a motor or a generator.

[0004] In another embodiment, an electric machine includes a stator assembly coupled to an engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component and a stator disposed on a support surface of the stator support structure. The electric machine further includes a rotor assembly that includes a rotor support structure directly connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure. The rotor is disposed radially inward of the stator such that the stator assembly circumferentially surrounds the rotor. In an embodiment, the rotor rotates with the shaft to generate an electrical signal. In an embodiment, the electric machine receives electrical power from an external source to provide rotational energy to the shaft.

[0005] In another embodiment, the electric machine includes a stator assembly coupled to the engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component. The stator is disposed on a support surface of the stator support structure. The electric machine also includes an electric machine shaft that is coupled to an end of the shaft of the propulsion engine via an intermediate shaft member that extends axially between the end of the shaft and the electric machine shaft. The electric machine also includes a bearing support frame extending from the propulsion engine, the bearing support frame including an axial portion that extends in the axial direction. The electric machine also includes an electric machine bearing extending radially from the axial portion of the bearing support frame to rotatably contact the electric machine shaft. The electric machine also includes a seal member axially disposed rearward of the electric machine bearing, the seal member extending from the axial portion of the bearing support frame to the electric machine shaft. The electric machine also includes a rotor assembly that includes a rotor support structure connected to the electric machine shaft and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator. In an embodiment, the rotor rotates with the shaft of the propulsion engine via the intermediate shaft member to generate an electrical signal. In an embodiment, the electric machine receives electrical power from an external source to provide rotational energy to the shaft.

[0006] In another embodiment, the electric machine includes a stator assembly coupled to the engine stator component of a propulsion engine. The stator assembly includes a stator support assembly fixedly attached to the engine stator component and a stator disposed on a support surface of the stator support structure. The electric machine also includes an electric machine shaft that is coupled to an end of the shaft of the propulsion engine via an intermediate shaft member that extends axially between the end of the shaft and the electric machine shaft. The electric machine also includes a bearing support frame extending from the propulsion engine, the bearing support frame defining a bearing cavity with the electric machine shaft. The electric machine also includes first and second electric machine bearings extending radially from the bearing support frame to rotatably contact the electric machine shaft. The electric machine also includes a seal member axially disposed rearward of the electric machine bearings, the seal member extending from the bearing support frame to the electric machine shaft. The electric machine also includes a rotor support structure connected to the electric machine shaft and a rotor attached to the rotor support structure. The rotor rotates with the electric machine shaft to exchange energy with the shaft of the propulsion engine.

[0007] In another embodiment, a propulsion engine includes a core section that generates exhaust gas traveling in an axial direction and a turbine section coupled to a shaft. The turbine section receives the exhaust gas and generates mechanical energy to rotate the shaft. The propulsion engine further includes a turbine frame attached to the turbine section, and the turbine frame includes a housing coupled to the turbine section and an inner hub that supports the shaft via a bearing assembly, the bearing assembly including an engine bearing that supports the shaft. The propulsion engine further includes an electric machine that includes: a stator assembly including a stator support assembly attached to the inner hub and a stator attached to a stator support structure; an electric machine shaft coupled to an end of the shaft via an intermediate shaft member that axially extends between the end of the shaft and the electric machine shaft; a bearing support frame attached to the inner hub and radially inwardly extending therefrom to define a bearing cavity extending between the bearing support frame and the electric machine shaft; an electric machine bearing radially extending from the bearing support frame to rotatably contact the electric machine shaft; and a rotor assembly. The rotor assembly includes a rotor support structure connected to the electric machine shaft and a rotor attached to the rotor support structure and radially inwardly extending from the stator. The rotor rotates with the shaft via the intermediate shaft member to exchange energy with the shaft.

[0008] Additional features, advantages, and embodiments of the processes and systems described herein will be set forth in the following detailed description, and, in part, based on the teachings disclosed herein, those of ordinary skill in the art will readily appreciate such features, advantages, and embodiments are contemplated and considered within the scope of the present disclosure.

[0009] It should be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and characteristics of the subject matter claimed and described herein. The accompanying drawings are provided to facilitate a further understanding of the various embodiments and are incorporated into and form a part of this specification. The drawings illustrate the various embodiments described herein and, together with the description, are used to explain the principles and operations of the subject matter claimed and described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The embodiments illustrated in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, in which like structures are denoted with like reference numerals and in which:

[0011] Figure 1 A cross-sectional view above the central axis A-A of the propulsion engine depicted in accordance with one or more embodiments described herein Figure 1 is depicted;

[0012] Figure 2 A magnified view of the electric machine of the propulsion engine depicted in accordance with one or more embodiments described herein Figure 1 is depicted;

[0013] Figure 3 Schematically depicts a cross-sectional view of an electric machine that can be incorporated into a propulsion engine as described herein into the Figure 1 propulsion engine depicted therein;

[0014] Figure 4 Schematically depicts a cross-sectional view of an electric machine that can be incorporated into a propulsion engine as described herein into the Figure 1 propulsion engine depicted therein; and

[0015] Figure 5 Schematically depicts a cross-sectional view of an electric machine that can be incorporated into a propulsion engine as described herein into the Figure 1 propulsion engine depicted therein. DETAILED DESCRIPTION

[0016] Reference will now be made to an electric machine for integration into a propulsion engine, such as a turbine engine. The electric machines described herein can be disposed at various axial positions within the propulsion engine (e.g., at the rear end of the propulsion engine, between the ends of the shaft of the propulsion engine) to facilitate rotational energy exchange between the shaft and the electric machine. For example, the electric machines described herein can include a stator assembly coupled to an engine stator component and a rotor assembly connected to the shaft of the propulsion engine such that the rotor of the rotor assembly rotates with the shaft to facilitate rotational energy exchange between the rotor assembly and the shaft. The electric machines described herein can operate in a generator mode, where rotational energy from the shaft generates an electrical signal in the stator that is provided by an electrical connector to other components of the propulsion engine or the aircraft; and in a motor mode, where electrical power is provided to the electric machine from an external source (e.g., an electrical storage device disposed on the aircraft) such that the rotor changes the rotational speed of the shaft.

[0017] In embodiments, the rotor assembly can be directly or indirectly attached to the shaft of the propulsion engine using different attachment structures that have different effects on the vibration of the shaft. For example, in embodiments, the rotor assembly includes a rotor support structure directly connected to the shaft of the propulsion engine such that the rotor assembly is supported by a bearing assembly that has been incorporated into the propulsion engine. In such embodiments, the rotor support assembly can be designed to have a desired effect on the natural vibration frequency of the shaft of the propulsion engine. For example, in embodiments, the structure of the rotor support structure is designed to change the vibration frequency of the shaft. In embodiments, the electrical load of the electric machine (e.g., connected via switchable coils in the rotor and stator) can be adjusted to controllably damp the vibration of the shaft of the propulsion engine to improve its long-term operability.

[0018] In an embodiment, the rotor assembly is indirectly attached to the shaft of the propulsion engine via a motor shaft, the motor shaft being rotatably coupled to the shaft of the propulsion engine, wherein an intermediate shaft member allows for axial and radial displacement of the motor shaft. The motor in such an embodiment can be supported by its own generator bearings to protect the motor from the vibrations of the shaft of the propulsion engine. An advantage of this separate shaft and bearing embodiment is also that the intermediate shaft member can decouple the motor shaft from the engine shaft, thereby protecting the engine from the motor in the event of a failure.

[0019] In an embodiment, the motor can be positioned at the rear of the propulsion engine (e.g., near the turbine rear frame). This positioning advantageously allows for easy maintenance and repair of the motor when the propulsion engine and the motor are installed on an aircraft (e.g., on a wing, on a fuselage, etc.). Additionally, in an embodiment, the motor can be positioned within the tail cone of the propulsion engine and can be directly accessed for repair after non-invasive procedures (e.g., opening the core cowl, removing the aft skin, and removing the tail cone) are performed on the remainder of the propulsion engine. In this way, the motor can be effectively maintained without disturbing the operation of other components of the propulsion engine. Further, the various components of the motor (e.g., the rotor assembly and the stator assembly) can be designed to allow for their independent removal from the propulsion engine. This non-invasive access to the motor advantageously facilitates the maintenance and repair of the motor when the propulsion engine is installed on an aircraft (e.g., on the wing, fuselage, etc.) of the aircraft.

[0020] Reference Figure 1 , a propulsion engine 100 is schematically depicted. Depending on the implementation, the propulsion engine 100 can take various forms. In the embodiments described herein, the propulsion engine 100 is a high-bypass turbofan engine. However, other types of turbine engines are contemplated and are within the scope of the present disclosure. As Figure 1As shown, the propulsion engine 100 includes an electric machine 300 disposed in the rear portion 104 of the propulsion engine 100. The rear portion 104 is axially disposed downstream of the core portion 220 of the propulsion engine 100 (e.g., in a direction parallel to the central axis A-A of the propulsion engine 100). In an embodiment, the electric machine 300 converts mechanical energy generated by the propulsion engine 100 (e.g., generated from the exhaust gas produced in the core portion 220) into electrical energy, which can be used to power electrical devices of the propulsion engine 100 or components disposed elsewhere on the aircraft (including components incorporating the propulsion engine 100). As described herein, positioning the electric machine 300 in the rear portion 104 of the propulsion engine 100 advantageously allows the electric machine 300 to be easily maintained, repaired, and replaced when the propulsion engine 100 is disposed on the aircraft (e.g., on the wing or fuselage of the aircraft). The electric machine 300 is designed to be integrated into the propulsion engine 100 via a set of connections that can be removed without invasively disassembling the entire propulsion engine 100 (e.g., removed without separating the propulsion engine 100 from the aircraft).

[0021] In an embodiment, the electric machine 300 may be attached to the inner hub 226 of the turbine rear frame 222 of the propulsion engine 100. Example embodiments of the structure of the electric machine 300 are described in more detail herein. Still referring to Figure 1 , it should be understood that the depicted arrangement of the propulsion engine 100 is merely exemplary and not limiting. For example, in an alternative embodiment, the electric machine 300 may be axially disposed in front of the core portion 220.

[0022] Positioning the electric machine 300 in the rear portion 104 provides accessibility but presents additional design considerations for the propulsion engine 100. The exhaust gas generated via the core portion 220 is at a relatively high temperature (e.g., exceeding about 700 °C or higher in various embodiments), which makes it beneficial to cool the electric machine 300. Additionally, the rear portion 104 of the propulsion engine 100 may not be directly connected to the aircraft incorporating the propulsion engine 100. In view of this, electrical signals directed to and from the electric machine 300 are directed through the propulsion engine 100. In an embodiment, for example, the propulsion engine 100 includes an electrical system ( Figure 1 not depicted in), which includes a plurality of electrical wires connecting the electric machine 300 to an electric machine control unit ( Figure 1 not depicted in). In an embodiment, the electrical wires are disposed within a cooling duct that supplies coolant to the rear portion 104 (e.g., from a bypass section radially outwardly disposed from the core portion 220). In an embodiment, the electrical wires are disposed outside the cooling duct.

[0023] In an embodiment, the motor control unit converts the electrical signal generated by the motor 300 (between an alternating current signal and a direct current signal, or vice versa) for providing to the propulsion engine 100 or additional components incorporated into the aircraft. In an embodiment, as described in more detail herein, the motor control unit may also provide a control signal to the motor 300 to change its operating mode (e.g., between a generator mode and a motor mode) and / or its load, thereby changing the rotational energy exchange between the motor 300 and additional components of the propulsion engine 100. In an embodiment, the motor control unit may be disposed at a location within the propulsion engine 100 that is displaced from the motor 300 (e.g., axially forward of the core section 220), or elsewhere on the aircraft (e.g., in a pylon).

[0024] Still referring to Figure 1 , the propulsion engine 100 includes a fan 201, a low-pressure compressor 202, a high-pressure compressor 204, and a combustor 206. The combustor 206 mixes air compressed by the high-pressure compressor 204 with fuel to generate combustion gases that flow downstream through a high-pressure turbine 208 and a low-pressure turbine 210 to produce pressurized exhaust. A first shaft 212 couples the high-pressure compressor 204 to the high-pressure turbine 208. A second shaft 216 couples the low-pressure turbine 210 to the fan 201 and the low-pressure compressor 202. In an embodiment, the high-pressure compressor 204, the combustor 206, and the high-pressure turbine 208 may together form a core section 220. The core section 220 may generate combustion gases that are directed to the low-pressure turbine 210, which in turn powers the fan 201 via the second shaft 216. The low-pressure turbine 210 may include multiple rows of blades that rotate in response to the combustion gases from the core section 220, thereby rotating the second shaft 216 to power the fan 201, the low-pressure compressor 202, and the motor 300.

[0025] A turbine rear frame 222 is disposed behind the low-pressure turbine 210 (e.g., offset from the low-pressure turbine 210 in a rearward direction (e.g., axial direction 272) extending parallel to the central axis A-A). The turbine rear frame 222 includes a plurality of struts 224 extending between an inner hub 226 and an outer casing 228. The turbine rear frame 222 provides an exhaust flow path for the exhaust flowing out of the low-pressure turbine 210. The inner hub 226 and the outer casing 228 may circumferentially surround the second shaft 216 and the plurality of struts 224 may be distributed around the second shaft 216. In an embodiment, the plurality of struts 224 function as exit guide vanes to straighten the exhaust gas flow, and the exhaust gas flow may flow through a tail cone 230 to improve the performance of the propulsion engine 100. It should be understood that the turbine rear frame 222 may include any number of struts 224 in any arrangement consistent with the present disclosure.

[0026] Still referring to Figure 1, the propulsion engine 100 includes a core cowl 250 and a rear skin 252. The core cowl 250 depicts the flow path of the air compressed by the fan 201. In an embodiment, the rear skin 252 is connected to the outer shell of the turbine rear frame 222 via a bolt connection (not depicted). In an embodiment, the exhaust gas exits the propulsion engine 100 via an outlet 254 defined by the turbine rear frame 222, the rear skin 252, and the tail cone 230.

[0027] Now referring to Figure 2 , a detailed view of a cross-sectional portion of the electric machine 300 depicted within the dashed boundary of Figure 1 is shown. In the depicted embodiment, the electric machine 300 includes a stator assembly 302 and a rotor assembly 304. The stator assembly 302 is directly connected to the propulsion engine 100 via a first engine stator component 260 and a second engine stator component 270. The first engine stator component 260 and the second engine stator component 270 may vary depending on the specific location where the electric machine 300 is disposed within the propulsion engine 100. For example, as described herein with respect to Figure 1 , the electric machine 300 is disposed in the rear portion 104 of the propulsion engine 100. In such an embodiment, the first engine stator component 260 may be a flow-defining structure, such as Figure 1 the turbine rear frame 222 depicted in

[0028] (e.g., the stator assembly 302 may be attached to the inner hub 226), and the second engine stator component 270 may be another component that radially extends between the second shaft 216 and the inner hub 226 (e.g., a turbine component, such as a bearing support structure, etc.). Alternative positions of the electric machine 300 are contemplated and within the scope of the present disclosure. For example, in an embodiment, the electric machine 300 is disposed between the end of the second shaft 216 (e.g., axially forward of the rear end 217 of the second shaft 216 and the turbine rear frame 222). In such an embodiment, the first engine stator component 260 may be another flow-path defining structure (e.g., an intermediate turbine frame, etc.). Various connection points between the electric machine 300 and the propulsion engine 100 are contemplated and within the scope of the present disclosure.The stator assembly 302 includes a stator 314 and the rotor assembly 304 includes a rotor 346. In the depicted embodiment, the rotor assembly 304 is disposed radially inward of the stator assembly 302 (e.g., the entire rotor assembly 304 is disposed closer to the second shaft 216 than the stator assembly 302). In an embodiment, the stator assembly 302 circumferentially surrounds the rotor assembly 304 such that the rotor assembly 304 is radially disposed between the stator assembly 302 and the second shaft 216 of the propulsion engine 100. In an embodiment, the electric machine 300 operates as a generator to convert the rotational energy of the second shaft 216 (e.g., during the flight operation of the propulsion engine 100) into electrical energy that can be transmitted to other components of the aircraft. In an embodiment, the electric machine 300 operates as a motor to provide torque to the second shaft 216 (e.g., to improve the operating efficiency of the propulsion engine 100).

[0029] The interior rotor configuration of the electric machine 300 facilitates its compactness (e.g., aerodynamic performance) and operability. For example, during operation of the electric machine 300, the interior rotor configuration of the electric machine 300 can promote its long-term operability in embodiments where the stator assembly 302 is disposed radially inward of the rotor assembly 304 by reducing the rotational loads applied to the structural components that support the rotor 346. Additionally, Figure 2 the interior rotor configuration of the electric machine 300 depicted herein can help the stator assembly 302 act as a shield to prevent damaged rotor components from traveling in the radially outward direction and affecting additional components of the propulsion engine 100. For example, if the electric machine 300 fails, a portion of the rotor assembly 304 may break and become disconnected from the second shaft 216. If unobstructed, such damaged components could interfere with the operation of the propulsion engine 100. However, due to the interior rotor structure of the electric machine 300, such damaged rotor components are contained within the rotor cavity 370 defined by the stator assembly 302. The containment of debris by the stator assembly 302 reduces the likelihood that a motor failure will affect the operation of other components of the propulsion engine 100 or high-energy components released from the propulsion engine 100. Embodiments with an exterior rotor configuration are contemplated and within the scope of the present disclosure, but may include a debris shield disposed radially outside of the rotor assembly 304.

[0030] In Figure 2In the illustrated embodiment, the electric machine 300 is directly connected to the second shaft 216 via the rotor support structure 338 of the rotor assembly 304. In an embodiment, the rotor support structure 338 includes an attachment element (e.g., a groove, a protrusion, etc., not shown) that slidably engages a corresponding attachment element on the second shaft 216. For example, in an embodiment, the rotor support structure 338 may slidably engage the second shaft 216 at the rear end 217 of the second shaft 216. A lock nut (not depicted) may fix the rotor support structure 338 to the second shaft 216 such that the rotor assembly 304 rotates with the second shaft 216 to facilitate power generation via the rotation of the second shaft 216.

[0031] Such an embodiment in which the rotor assembly 304 is directly attached to the second shaft 216 may be referred to herein as an "embedded generator embodiment". In the embedded generator embodiment, the rotor assembly 304 may be at least partially supported by a bearing assembly (e.g., an engine bearing assembly that supports the rear portion 104 of the propulsion engine 100 and is axially disposed near the turbine rear frame 222 - not depicted) that supports the second shaft 216. The embedded generator embodiment may be beneficial because the electric machine 300 can be used as a shaft natural frequency damper. In an embodiment, components of the rotor assembly 304 (e.g., the rotor support structure 338) may be structurally designed to modify the natural frequency of the second shaft 216 (e.g., change the natural vibration frequency of the second shaft 216 compared to an embodiment without the electric machine 300 incorporated). For example, in an embodiment, the stiffness and volume of the rotor support structure 338 may be selected to remove the natural vibration frequency of the second shaft 216 from a range in which the vibration of the second shaft 216 may excite vibration modes of other components of the propulsion engine 100, thereby avoiding structural integrity issues associated with high amplitude oscillations.

[0032] In an embodiment, the electric machine 300 may be designed to variably affect the natural vibration frequency of the second shaft 216 via its external control. In the depicted embodiment, for example, the electric machine 300 is communicatively coupled (e.g., via the wires 336 and 342 and the electrical connection device 328 described herein) to the electric machine control unit 380. The electric machine control unit 380 may control the electric machine 300 by changing the electrical load based on the power demand. In an embodiment, the electric machine control unit 380 is disposed at an axial position of the propulsion engine 100 that is different from the electric machine 300. In an embodiment, the electric machine control unit 380 is disposed at the same axial position as the electric machine 100 within the propulsion engine.

[0033] In an embodiment, for example, the motor control unit 380 receives instructions from another component associated with the aircraft (e.g., the engine power control unit) to adjust the motor load to change the rotational energy extracted from the second shaft 216 via the rotation of the rotor 346, thereby controllably suppressing the vibration of the second shaft 216. For example, the motor control unit 380 may change the electrical load of the motor 300 (e.g., by disconnecting and reconnecting the electrical connection between its coils) in response to the detected vibration of the second shaft 216 in order to suppress the detected vibration. This electrical load control of the motor control unit 380 may occur in both the generator operating mode and the motor operating mode of the motor 300.

[0034] Still referring to Figure 2 , the rotor assembly 304 further includes a rotor attachment arm 340 that axially extends forward from an end of the rotor support structure 338. The rotor attachment arm 340 holds the rotor 346 in a spaced-apart relationship from the stator 314 and the second shaft 216. In an embodiment, the rotor 346 includes a plurality of permanent magnets circumferentially distributed around the stator 314 such that the rotation of the rotor 346 around the stator 314 generates an AC power signal. It should be understood that alternative configurations of the rotor 346 can be envisioned depending on the implementation of the motor 300. For example, in an embodiment, the rotor 346 may include a plurality of electromagnets and active circuitry. Various embodiments are envisioned in which the motor 300 is configured as an induction generator, a switched reluctance generator, an asynchronous AC motor, or any suitable type of generator.

[0035] In an embodiment, the stator assembly 302 circumferentially surrounds the rotor assembly 304. In an embodiment, the stator assembly 302 (e.g., the stator support assembly 308 described herein) includes a plurality of circumferential segments, each of which can be separately removed from the propulsion engine 100 to facilitate its removal. In embodiments where the motor is centrally disposed within the propulsion engine 100 (e.g., away from the end of the second shaft 216), such an embodiment incorporating a plurality of circumferential segments may be particularly beneficial because accessing the motor 300 for maintenance or replacement may be more time-consuming in such embodiments.

[0036] In the depicted embodiment, the stator assembly 302 is attached to the first engine stator component 260 and the second engine stator component 270 via the first connection bolt 327 and the second connection bolt 329, respectively. The stator assembly 302 includes a stator support assembly 308 that holds the stator 314 in a desired position relative to the rotor 346. The stator support assembly 308 includes stator support arms 312. The stator support arms 312 extend in the axial direction 272 (e.g., parallel to the second shaft 216) and define a stator support surface 313 to which the stator 314 is attached.

[0037] In an embodiment, the stator support arm 312 extends over the entire rotor 346 in the axial direction 272 to define a rotor cavity 370 that extends between the stator support arm 312 and the second shaft 216. In an embodiment, the stator support arm 312 is longer than the rotor 346 in the axial direction 272. In addition to providing structural support for the stator 314, the stator support arm 312 also helps to contain any debris associated with the rotor assembly 304 (e.g., in combination with a debris shield disposed radially outside the stator support arm 302), thereby preventing the release of high-energy components outside the propulsion engine 100. That is, the stator support arm 312 can be used as a shield to prevent a failure of the rotor assembly 304 from interfering with the operation of other components of the propulsion engine 100, or to prevent the rotor assembly 304 from launching high-energy debris outside the propulsion engine 100. In an embodiment, the stator support arm 312 is the only containment mechanism of the propulsion engine 100 for containing such debris from the rotor assembly 304. That is, the inner rotor configuration of the electric machine 300 can eliminate the need for a debris shield around the electric machine 300.

[0038] In an embodiment, the stator support arm 312 includes a substantially cylindrical structure around the second shaft 216. In an embodiment, the substantially cylindrical structure is an integral continuum. In an embodiment, the stator support arm 312 includes a plurality of circumferential segments, each of the plurality of circumferential segments being connected to each other to facilitate the separate removal of each circumferential segment radially away from the second shaft 216. In an embodiment, the plurality of circumferential segments are circumferentially discontinuous. That is, in such an embodiment, the stator support arm 312 can include a gap around its circumference.

[0039] In an embodiment, the electrical and fluid connections of the electric machine 300 are facilitated by the structure of the stator support assembly 308. For example, in Figure 2 the embodiment shown, the electric machine 300 includes a connector support 316 that extends radially between the first engine stator component 260 and the stator support arm 312. In an embodiment, the connector support 316 includes at least one opening 318 for supporting the electrical connection device 328. It should be understood that embodiments can also be envisioned in which the electric machine 300 does not include the connector support 316, or the connector support 316 is disposed in a manner different from Figure 2Positions with different shown positions. The electrical connection device 328 can conductively connect the wire 336 from the stator 314 to the external wire 342. In an embodiment, the connector support 316 serves as a holder for the electrical connection device 328 to facilitate electrically connecting the motor 300 to other components of the propulsion engine 100. In an embodiment, the connector support 316 includes a plurality of openings 318 distributed circumferentially around the stator support assembly 308. Electrical connectors can extend through each of the plurality of openings to facilitate providing electrical signals generated by the motor 300 to external components. It should be understood that alternative positions are envisioned for the electrical connection device 328. That is, the electrical connection device 328 can be disposed along the wires 336 and 342 at an alternative position different from Figure 2 the position depicted therein (e.g., axially forward of the shaft of the motor 300). In such embodiments with an alternative positioning of the electrical connection device 328, the motor 300 may not include the connector support 316.

[0040] In an embodiment, the motor 300 includes a cooling system 350 that distributes coolant to various parts of the motor 300. In the depicted embodiment, the cooling system 350 includes an inlet manifold 352 and a stator manifold 354. The inlet manifold 352 receives coolant air from a part of the propulsion engine 100 external to the motor 300. In an embodiment, the inlet manifold 352 is part of or connected to another cooling duct of the propulsion engine 100. In an embodiment, the inlet manifold 352 can be directed through the first engine stator component 260 (e.g., through Figure 1 one of the struts 224 of the turbine rear frame 222 depicted therein). The stator manifold 354 supplies coolant to the stator 314 to keep its temperature within a suitable operating range. In an embodiment, one or more of the wires and the electrical connection device are disposed within the cooling system 350. For example, in the depicted embodiment, the wires 336 and 342 extend through the stator manifold 354 and the inlet manifold 356 respectively, and are conductively connected within the stator manifold 354 via the electrical connection device 328. Embodiments where the wires are disposed outside the cooling system 350 are also envisioned. In an embodiment, the stator support arm 312 includes holes or openings to lead to cooling manifolds different from Figure 2 those depicted therein.

[0041] In Figure 2In the illustrated embodiment, the electrical and fluid connections of the cooling system 350 are provided at the rear end of the stator 314 (e.g., via the connection portion 358 of the stator manifold 354). It should be understood that alternative embodiments are contemplated and within the scope of the present disclosure. For example, in an embodiment, the electrical wire 336 may extend from the front axial end of the stator 314, and the stator manifold 354 may extend through the stator support arm 312 to facilitate attachment and connection to the front axial end of the stator (e.g., the stator manifold 354 may not include a connection portion 358 including a bend as in the depicted embodiment). In such an embodiment, the electrical connection device 328 may also be provided axially forward of the stator 314. For example, the electrical connection device 328 may be supported inside or outside a portion of the stator manifold 354 that extends through the stator support arm 312 to facilitate electrical connection to the external electrical wire 342. Such an embodiment may not include the connector support 316 (the depicted embodiment may also not include the connector support 316). Various combinations of electrical and fluid coupling structures are contemplated and within the scope of the present disclosure.

[0042] In an embodiment, the electric machine 300 includes a thermal shield 348. In an embodiment, the thermal shield 348 is not directly attached to the second shaft 216, but circumferentially surrounds the rear end 217 of the second shaft 216, the stator assembly 302, and the rotor assembly 304. In an embodiment, the thermal shield 348 is attached to the first engine stator component 260. For example, in an embodiment, the thermal shield 348 is attached to the connection flange 310 of the first engine stator component 260 via the first connection bolt 327. In an embodiment, the thermal shield 348 includes at least two components. In an embodiment, for example, the thermal shield 348 includes a stator portion that circumferentially surrounds the stator assembly 302 and a rotor portion that extends axially rearward of the rotor 346. In an embodiment, the individual portions of the thermal shield 348 may be removed separately from the propulsion engine 100 to facilitate access to the rotor assembly 304 without disrupting the connection of the stator assembly 302.

[0043] Figure 2 The views depicted therein correspond to a single circumferential cross-section of the electric machine 300. Thus, it should be understood that the electric machine 300 may include any number of Figure 2 components distributed around the circumference of the second shaft 216. Figure 2 The components depicted therein may also be axially separated. That is, Figure 2 each component depicted therein is a continuous section (e.g., the stator support arm 312) that may be divided into multiple segments that extend in the axial direction 272 and extend into each other. In an embodiment, the electric machine 300 includes a circumferential distribution around it similar to Figure 2The multiple cooling systems of the cooling system 350 depicted (e.g., having multiple manifolds, electrical connectors, and wires extending therethrough). Additionally, components of the motor 300 (e.g., the stator support assembly 308, the thermal shield 348, etc.) can be connected to the propulsion engine 100 at any number of points along the circumference of the propulsion engine 100. That is, the motor 300 can include a plurality of first connection bolts 327 and second connection bolts 329 distributed around its circumference.

[0044] Various components of the motor 300 and the propulsion engine 100 have been described, and now the various advantages regarding Figure 2 and Figure 3 the described structure can be understood. For example, referring to Figure 1 , in order to make the motor 300 fully accessible, the tail cone 230 can be removed. After removing the tail cone 230, at least a portion of the motor 300 can be removed from the propulsion engine 100. Depending on the type of operation being performed and the process being followed, all or a portion of the motor 300 can be removed. For example, in an embodiment, the plurality of first connection bolts 327 and second connection bolts 329 that attach the stator assembly 302 to the first engine stator component 260 and the second engine stator component 270 can be removed to facilitate the removal of the thermal shield 348. Then the connection between the rotor support structure 338 and the second shaft 216 can be loosened, thereby facilitating the removal of the rotor assembly 304 for replacement and / or maintenance. The stator assembly 302 can also be removed from the first engine stator component 260 and the second engine stator component 270.

[0045] In an embodiment, instead of removing the stator assembly 302, the rotor assembly 304 can be removed from the second shaft 216 without removing the connections at the plurality of first connection bolts 327 and second connection bolts 329. The non-radially overlapping structure of the stator assembly 302 and the rotor assembly 304 facilitates accessing and removing the rotor assembly 304 from the propulsion engine 100 without damaging the stator assembly 302, facilitating rapid and efficient maintenance operations.

[0046] The manner in which the motor 300 is positioned and connected within the propulsion engine 100 thus facilitates access to and removal of the motor 300 without removing components of the propulsion engine 100 that are located in front of the turbine rear frame 222 (e.g., Figure 2Any component in the opposite direction of the axial direction 272 depicted (or radially inward). When the propulsion engine 100 is disposed on the wing or fuselage of the aircraft, approaching the motor 300 in such a non-invasive manner facilitates the maintenance or replacement of various components of the motor 300, which minimizes the time during which the aircraft may be inoperable if the motor 300 requires repair. In addition, the manner in which the motor 300 is connected to various components of the propulsion engine 100 provides a streamlined process for removing the motor 300 from the propulsion engine 100.

[0047] Now refer to Figure 3 , a cross-sectional view of a motor 400 that can be integrated into a propulsion engine (such as the propulsion engine 100 described herein with respect to Figure 1 is schematically depicted. The motor 400 can include components of the motor 300 described herein with respect to Figure 2 . Thus, the same reference numerals are used in Figure 3 to indicate the combination of such identical components. The motor 400 is also an embedded generator embodiment and includes a rotor 346 fixedly attached to a second shaft 216. The motor 400 includes a stator assembly 302 described with respect to the motor 300 depicted in Figure 2 . The motor 400 further includes a rotor assembly 402 that structurally differs from the rotor assembly 304 described with respect to Figure 3 in that the rotor assembly 402 includes a rotor support structure 404 that extends axially forward from the point where it is attached to the second shaft 216. In an embodiment, the rotor support structure 404 is connected to the second shaft 216 at the rear end 217 of the second shaft 216 (e.g., by engaging a feature on the second shaft 216). As shown in Figure 3 , the rotor support structure 404 extends in the axially forward direction, and the rotor attachment arm 340 extends axially backward from the end of the rotor support structure 404. This axial forward extension of the rotor support structure 404 provides additional space behind the motor 400 that is used to handle additional components (such as coolant manifolds, fuel supply lines, etc.) that can be incorporated into the motor 400 and the propulsion engine 100. In an embodiment, the rotor support structure 404 extends only in the radial direction 274.

[0048] Now refer to Figure 4 , a cross-sectional view of a motor 500 that can be integrated into a propulsion engine (such as the propulsion engine 100 described herein with respect to Figure 1 is schematically depicted. The motor 500 can include components of the motor 300 described herein with respect to Figure 2 . Thus, in Figure 4The same reference numerals are used in the drawings to indicate the combination of such identical components. The motor 500 is different from the motor 300 in that the motor 500 is not directly connected to the second shaft 216, but is indirectly connected to the second shaft 216 via the motor shaft 502. The motor shaft 502 is attached to the rear end 217 of the second shaft 216 through an intermediate shaft member 504. In an embodiment, the intermediate shaft member 504 is attached to the second shaft 216 such that the axial and radial vibrations of the second shaft 216 are not transmitted to the motor shaft 502. For example, in an embodiment, the intermediate shaft member 504 includes a sleeve shaft that includes a first spline (not shown) at its front end 505. The first spline can be inserted into an opening at the rear end 217 of the second shaft 216 to rotatably couple the second shaft 216 and the motor shaft 502. A second spline (not depicted) at the rear end 507 of the intermediate shaft member 504 can be inserted into the connection end 503 of the motor shaft 502. Such a spline connection between the motor shaft 502 and the second shaft 216 can allow for axial and radial movement of the motor shaft 502 relative to the second shaft 216, such that the motor 500 does not change the natural vibration frequency of the second shaft 216. In an embodiment, the intermediate shaft member 504 can include a bellows spring member instead of a sleeve shaft to allow for relative axial and radial movement of the motor shaft 502 relative to the second shaft 216. In an embodiment, the intermediate shaft member 504 includes a shear section that is configured to separate (e.g., break) when placed under a predetermined shear load. In an embodiment, the intermediate shaft member 504 and the motor shaft 502 can be integrated into a single component.

[0049] The motor shaft 502 is radially supported via a generator bearing assembly 516, and the generator bearing assembly 516 is attached to the second engine stator component 270 via a bolt connection 552. The generator bearing assembly 516 includes a bearing support frame 514 that extends radially between the motor shaft 502 and the second engine stator component 270. As depicted, the bearing support frame 514 includes an axial portion 518 that defines a bearing cavity 520 together with the motor shaft 502. A first bearing support arm 519 and a second bearing support arm 521 extend from the bearing support frame 514 in the axial direction 272. A first generator bearing 522 extends between the first bearing support arm 519 and a first portion of the motor shaft 502, and a second generator bearing 524 extends between the second bearing support arm 521 and a second portion of the motor shaft 502 to rotatably contact the motor shaft 502 (e.g., the inner rings connected to the motor shaft 502 can accommodate the first generator bearing 522 and the second generator bearing 524 to provide such rotatable contact). Depending on the implementation, the first generator bearing 522 and the second generator bearing 524 can include various types of bearings (e.g., ball bearings, roller bearings, etc.). The first generator bearing 522 and the second generator bearing 524 protect the motor 500 from the radial and axial movement of the second shaft 216.

[0050] Figure 4 Also depicted is an engine bearing assembly 538 associated with the propulsion engine 100. For example, in an embodiment, the engine bearing assembly 538 may support the second shaft 216 via a second engine stator component 270 (e.g., the second engine stator component 270 may include a support structure that extends radially inward from an inner hub 226 of the turbine rear frame 222). The engine bearing assembly 538 includes an engine bearing support arm 540 extending from the second engine stator component 270. The engine bearing support arm 540 and the second shaft 216 define an engine bearing cavity 541. An engine bearing 542 is disposed within the engine bearing cavity 541 and extends between the engine bearing support arm 540 and the second shaft 216. The engine bearing 542 rotatably contacts the second shaft 216 such that the second engine stator component 270 supports the second shaft 216.

[0051] Accordingly, the electric machine 500 is supported by dedicated bearings (e.g., a first generator bearing 522 and a second generator bearing 524) on the electric machine shaft 502 to protect the electric machine 500 from vibrations of the second shaft 216. In an embodiment, the engine bearing cavity 541 and the bearing cavity 520 are fluidly isolated from each other to mitigate the risk of contamination of the engine bearing assembly 538 during maintenance of the electric machine 500. For example, in Figure 4 the illustrated embodiment, the generator bearing assembly 516 includes a first seal member 526 extending between a first bearing support arm 519 and the electric machine shaft 502, and a second seal member 528 extending between a second bearing support arm 521 and the electric machine shaft 502. The first seal member 526 and the second seal member 528 may be constructed of a suitable compliant material (e.g., a labyrinth air seal) to create a seal at the interface between the first seal member 526 and the second seal member 528 and the electric machine shaft 502.

[0052] The engine bearing assembly 538 also includes a seal member 544 disposed between the engine bearing support arm 540 and the second shaft 216. The seal member 544 creates a seal at its interface with the second shaft 216. The seal member 544 is axially disposed between the engine bearing 542 and the generator bearing assembly 516 such that the engine bearing assembly 538 is fluidly isolated from the generator bearing assembly 516. This isolation of the bearing assemblies facilitates providing lubricant from separate sources to reduce the risk of contamination during maintenance. For example, in the depicted embodiment, the propulsion engine 100 includes an engine bearing lubrication system 546 and a generator bearing lubrication system 530. The generator bearing lubrication system 530 includes an oil supply line 531 supported by the bearing support frame 514. In an embodiment, the oil supply line 531 extends through an opening in the axial portion 518 into the bearing cavity 520. The generator bearing lubrication system 530 also includes an oil injector 532 that includes an outlet disposed proximate the first generator bearing 522 and the second generator bearing 524 such that during operation of the first generator bearing 522 and the second generator bearing 524, oil from a lubricant source (not shown) passes through the oil supply line 531 and is ejected onto the surfaces of the first generator bearing 522 and the second generator bearing 524 to provide lubrication and cooling. The generator bearing lubrication system 530 also includes an oil scavenging device 534 that facilitates oil circulation out of the bearing cavity 520.

[0053] The engine bearing lubrication system 546 includes an oil supply line 548 and an oil injector 550 that includes an outlet disposed proximate the engine bearing 542 to provide lubrication during operation of the engine bearing 542. By using separate bearing lubrication systems (e.g., separate oil supply lines 531 and 548) to provide lubricant to the generator bearing assembly 516 and the engine bearing assembly 538, Figure 4 the risk associated with performing maintenance on the electric machine 500 in the depicted embodiment is mitigated.

[0054] Although the depicted embodiment incorporates an oil-based generator bearing lubrication system 530 and an engine bearing lubrication system 546, it should be understood that alternative lubrication systems using different types of lubricants are contemplated and within the scope of the present disclosure. According to the present disclosure, various types of fluid-based lubricants (e.g., synthetic polymer-based lubricants), gas-based lubricants, or solid lubricants may also be used. Isolating the separate lubrication systems associated with the generator and engine bearings generally avoids complications in the engine bearing assembly due to maintenance of the electric machine 500, thereby avoiding interference with the operation of the remainder of the propulsion engine 100.

[0055] Still referring to Figure 4 the electric machine 500 is associated with the present disclosure with respect to Figure 2The described electric machine 300 is also different in that the electric machine includes a rotor assembly 506 that is structurally different from the rotor assemblies 304 described herein. The rotor assembly 506 includes a rotor support structure 508 attached to the electric machine shaft 502 via a mounting flange 510 of the electric machine shaft 502. The rotor support structure 508 is attached to the mounting flange 510 by connection bolts 512 that extend through the mounting flange 510 and the rotor support structure 508. The rotor support structure 508 extends from the electric machine shaft 502 and rotor attachment arms 340 axially extend therefrom to support the rotor 346 in a desired position. In an embodiment, the rotor support structure 508 extends diagonally from the electric machine shaft 502 (e.g., similar to the rotor support structures 338 and 404 described herein with respect to Figure 2 and Figure 3 ).

[0056] In the depicted embodiment, the rotor 346 is disposed radially inward of the stator assembly 302. As discussed herein, this inner rotor design facilitates the independent removal of the rotor assembly 506. Since the mounting flange 510 of the electric machine shaft 502 is disposed axially rearward of the bearing support frame 514, the connection bolts 512 can be accessed without removing the bearing support frame 514, which allows the rotor assembly 506 to be removed independently of the stator assembly 302. Additionally, due to the inner rotor construction of the electric machine 500, the stator support arms 312 can serve as a debris shield for containing any damaged components of the rotor assembly 506. It should be understood that embodiments incorporating various aspects of the electric machine 500 (e.g., the electric machine shaft 502, the intermediate shaft member 504, the generator bearing assembly 516) are also contemplated, where the rotor 346 is disposed radially outward of the stator assembly 302.

[0057] The separate shaft coupling of the electric machine 500 via the electric machine shaft 502 further facilitates separating the electric machine 500 from the propulsion engine 100 by disconnecting the intermediate shaft member 504. As Figure 4 shown, the propulsion engine 100 includes a separation device 536 extending from a second engine stator component 270. The separation device 536 axially overlaps the intermediate shaft member 504 such that upon activation of the separation device 536, the separation device 536 acts on the intermediate shaft member 504 to separate the electric machine shaft 502 from the second shaft 216 to protect the second shaft 216 from a failure of the electric machine 500 by mechanically disconnecting the electric machine 500 from the second shaft 216.

[0058] To facilitate removal of the electric machine 500 from the propulsion engine 100 via the splines of the intermediate shaft member 504, the manner in which the stator assembly 302 is connected to the propulsion engine 100 can be modified compared to the generator assembly 300 described herein with respect to Figure 3 . As Figure 4As shown, the stator assembly 302 is not directly connected to the second engine stator component 270, but rather to the bearing support frame 514. The bearing support frame 514 is connected to the second engine stator component 270 via a first connection bolt 552, and the stator support arm 312 is connected to the bearing support frame 514 via a second connection bolt 554. The axial portion 556 of the bearing support frame 514 extends between the first connection bolt 552 and the second connection bolt 554 to axially separate the stator support arm 312 from the second engine stator component 270. In an embodiment, the first connection bolt 552 can be removed to facilitate removal of the motor shaft 502 from the intermediate shaft member 502 via a spline connection. Thus, the spline coupling provided by the intermediate shaft member 504 facilitates removal of the entire motor 504 (e.g., the motor shaft 502, the bearing support frame 514, the generator bearing assembly 516, the rotor assembly 506, and the stator assembly 302) as a single module to reduce the risk of contamination. After removing the motor 500, the intermediate shaft member 502 can also be removed.

[0059] In an embodiment, the second connection bolt 554 can be loosened to facilitate removal of the stator assembly 302 without using the separation device 536 (e.g., removing the connection bolts 327, 554, and 512 can facilitate removal of the rotor assembly 506 and the stator assembly 302 from the propulsion engine 100 independent of the bearing support frame 514). Thus, the depicted design promotes flexibility in the operations that can be performed to remove the motor 500 (or portions thereof) from the propulsion engine 100. In an embodiment, the bearing support frame 514 and the stator support arm 312 can be constructed of different materials to achieve the desired functionality and durability. In an embodiment, the stator support arm 312 and the bearing support frame 514 are integrated into a single part.

[0060] Now referring Figure 5 to, a cross-sectional view of a motor 600 that can be integrated into a propulsion engine (e.g., the propulsion engine 100 described herein with respect to Figure 1 ) is schematically depicted. The motor 600 can include components of the motor 500 described herein with respect to Figure 5 . Accordingly, the same reference numerals are used in Figure 5 to denote the combination of such identical components. The motor 600 differs from the motor 500 described herein with respect to Figure 4 in that the motor 600 includes a generator bearing assembly 602 and an engine bearing assembly 604 that are disposed in a common reservoir 640 that is at least partially defined by the bearing support frame 514 and the second engine stator component 270. As Figure 5 shown, the generator bearing assembly 602 includes with respect to Figure 4the described first generator bearing 522 and second generator bearing 524, but includes only a single generator bearing seal member 622 axially disposed rearward of the second generator bearing 524. The engine bearing assembly 604 includes the engine bearing 542 as described with respect to Figure 4 the described engine bearing 542, but includes a single engine bearing seal member 606 axially disposed forward of the engine bearing 542. The seal members 622 and 606 seal a common reservoir 640 to contain lubricant supplied to the bearings.

[0061] In the electric machine 600, the common reservoir 640 is not axially sealed between the first generator bearing 522 and second generator bearing 524 and the engine bearing 542. That is, with respect to Figure 4 the described bearing cavities 520 and 541 are not fluidly isolated from each other. The lack of a seal between such bearings allows a common lubricant source to be used to lubricate the first generator bearing 522 and second generator bearing 524 and the engine bearing 542. For example, in the depicted embodiment, a bearing lubrication system 608 is used to supply lubricant to the engine bearing 542 and the first and second generator bearings 522 and 524. The bearing lubrication system 608 includes an oil supply line 610 extending from a lubricant source (not shown) into the coolant cavity 562. The oil supply line 610 branches into a generator portion 614 extending axially rearward into the bearing cavity 520 and an engine portion 612 extending axially forward into the bearing cavity 541. The oil nozzle 618 at the end of the generator portion 614 includes an outlet for supplying oil to the first generator bearing 522 and second generator bearing 524. The oil nozzle 620 disposed at the end of the engine portion 612 includes an outlet for supplying oil to the engine bearing 542. The bearing lubrication system 608 also includes one or more drain channels 626 disposed adjacent to each of the bearings 522, 524, and 542 for receiving oil after the oil has been applied to the bearings 522, 524, and 542. Embodiments may incorporate drain channels in a portion of the second engine stator component 270 disposed adjacent to the separation device 536. The drain channels 626, 628, 630 may drain oil near the bearings 522, 524, and 542 into the common reservoir 640. The scavenging device 624 may direct the oil to a scavenging line for filtration and reuse.

[0062] Thus, the common reservoir 640 of the electric machine 600 facilitates the use of one bearing lubrication system 608 (e.g., including a single oil supply line 610 from a lubricant source), and includes a simpler structure than the multiple lubrication systems (e.g., the generator bearing lubrication system 530 and the engine bearing lubrication system 546) associated with the Figure 4 described electric machine 500. As compared with the Figure 4Compared with the described electric machine 500, the reduction of the oil pipelines, seals, and connections in the electric machine 600 can reduce the weight and complexity of the electric machine 600.

[0063] In view of the foregoing description, it should be understood that the electric machine can be integrated into a propulsion engine of an aircraft. The stator assembly of the electric machine can be coupled to one or more engine stator components of the propulsion engine, and the rotor assembly can be directly or indirectly coupled to the shaft of the propulsion engine to facilitate rotational energy exchange between the shaft and the electric machine. The rotor assembly can be directly connected to the shaft by a rotor support structure attached to the shaft, or indirectly connected to the shaft via an intermediate shaft member and an electric machine shaft. In such an embodiment, the electric machine can be supported on its own bearings to protect the electric machine from the vibrations of the shaft and to protect the shaft from the vibrations of the electric machine. The electric machine can also be removed integrally by a spline connection with the intermediate shaft member to avoid the risk of magnetic contamination of the electric machine during maintenance. When the propulsion engine is installed on an aircraft, the electric machine can be constructed and positioned to facilitate its relatively easy access and removal for maintenance.

[0064] As used herein, the term "about" means that the quantity, size, formulation, parameter, and other quantities and characteristics are not and need not be exact, but can be approximate and / or larger or smaller as needed, reflecting tolerances, conversion factors, rounding, measurement errors, etc., and other factors known to those skilled in the art. When the term "about" (or "substantially" or "approximately") is used to describe the endpoints of a value or range, the particular value or endpoint being referred to is included. Whether or not the numerical values or endpoints of the ranges in the specification are recited with "about", two embodiments are described: one modified by "about" and one not modified by "about". It will be further understood that each endpoint of a range is significant relative to the other endpoint and is independent of the other endpoint. For example, the approximating language can refer to within a margin of 1%, 2%, 4%, 10%, 15%, or 20% of a single value, a range of values, and / or the endpoints of a defined range of values.

[0065] Directional terms (such as up, down, right, left, front, back, top, bottom) used herein are made only with reference to the drawings as drawn and are not intended to imply absolute orientation.

[0066] Unless otherwise expressly stated, no method set forth herein is intended to be construed as requiring its steps to be performed in a particular order, nor is any apparatus-specific orientation intended. Accordingly, in any aspect, if a method claim does not actually recite the order in which its steps are to be performed, or any apparatus claim does not actually recite the order or orientation of individual components, or if the steps are not otherwise specifically stated in the claims or specification to be limited to a particular order, or the components of the apparatus are not recited as to a particular order or orientation, then no order or orientation is intended to be inferred. This applies to any possible basis for non-explicit interpretation, including: logical issues related to step arrangement, operational flow, component order, or component orientation; the plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0067] As used herein, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" include plural referents. Thus, for example, a reference to "a" component includes aspects having two or more such components, unless the context clearly dictates otherwise.

[0068] A further aspect of the invention is provided by the subject matter of the following clauses:

[0069] 1. An electric machine, comprising: a stator assembly coupled to an engine stator component of a propulsion engine, the stator assembly including: a stator support assembly fixedly attached to the engine stator component; and a stator disposed on a support surface of the stator support structure; and a rotor assembly including a rotor support structure connected to a shaft of the propulsion engine and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator, wherein the rotor exchanges rotational energy with the shaft to operate as an electric motor or a generator.

[0070] 2. The electric machine according to any of the preceding clauses, wherein the stator assembly circumferentially surrounds the rotor assembly such that the rotor assembly is disposed radially between the shaft and the stator assembly.

[0071] 3. The electric machine according to any of the preceding clauses, wherein the stator support assembly includes stator support arms extending parallel to the shaft in an axial direction, the stator support arms defining the support surface, wherein the stator support arms are at least as long as the rotor assembly in the axial direction such that the entire rotor assembly is disposed in a rotor cavity defined by the stator support arms, and the stator support arms isolate the propulsion engine from the rotor assembly.

[0072] 4. The electric machine according to any of the preceding clauses further comprises: an electrical connection device, which is coupled to the stator support assembly; and an electrical wire, which extends from the stator to the electrical connection device.

[0073] 5. The electric machine according to any of the preceding clauses further comprises an electric machine control unit, which is electrically connected to the stator, wherein the electric machine control unit is configured to switch the operation of the electric machine between a generator mode in which electrical power is generated by rotation of the shaft and a motor mode in which the stator adds rotational energy to the shaft.

[0074] 6. The electric machine according to any of the preceding clauses, wherein the rotor assembly is directly connected to an end of the shaft.

[0075] 7. The electric machine according to any of the preceding clauses, wherein no part of the stator assembly axially extends behind the rotor assembly.

[0076] 8. The electric machine according to any of the preceding clauses further comprises: an electric machine shaft, which is coupled to an end of the shaft of the propulsion engine via an intermediate shaft member that axially extends between the shaft and the electric machine shaft; and a generator bearing assembly, which comprises: a bearing support frame, which extends between the electric machine shaft and the engine stator component; and a generator bearing, which supports the electric machine shaft, wherein the electric machine shaft rotates with the shaft of the propulsion shaft within the generator bearing to rotate the rotor.

[0077] 9. The electric machine according to any of the preceding clauses further comprises a cooling system, which comprises one or more cooling manifolds that direct coolant from a coolant source to areas adjacent to the stator and the rotor.

[0078] 10. An electric machine comprises: a stator assembly, which is coupled to an engine stator component of a propulsion engine, the stator assembly comprising: a stator support assembly, which is fixedly attached to the engine stator component; and a stator, which is disposed on a support surface of the stator support structure; and a rotor assembly, which comprises a rotor support structure directly connected to the shaft of the propulsion engine and a rotor attached to the rotor support structure, wherein: the rotor is disposed radially inward of the stator such that the stator assembly circumferentially surrounds the rotor, and at least one of the following: the rotor rotates with the shaft to generate an electrical signal, and the electric machine receives electrical power from an external source to provide rotational energy to the shaft.

[0079] 11. The electric machine according to any of the preceding clauses, wherein the rotor support structure is directly connected to the end of the shaft of the propulsion engine by a removable connection such that the rotor assembly can be removed independently from the propulsion engine.

[0080] 12. The electric machine according to any of the preceding clauses, wherein the rotor support structure is directly connected to the shaft between the ends of the shaft of the propulsion engine.

[0081] 13. The electric machine according to any of the preceding clauses, wherein the rotor support structure extends from the ends of the shaft in a radial direction and an axial direction to mechanically change the natural vibration mode of the shaft.

[0082] 14. The electric machine according to any of the preceding clauses, further comprising an electric machine control unit electrically connected to the stator, wherein the electric machine control unit is configured to actively adjust the electric machine load to affect the rotation of the electric machine, thereby suppressing the vibration of the shaft.

[0083] 15. The electric machine according to any of the preceding clauses, further comprising a cooling system including one or more cooling manifolds that direct coolant from a coolant source to areas adjacent to the stator and the rotor.

[0084] 16. The electric machine according to any of the preceding clauses, wherein the electrical wires extending from the stator are at least partially directed through the one or more cooling manifolds.

[0085] 17. An electric machine, comprising: a stator assembly coupled to an engine stator component of a propulsion engine, the stator assembly including: a stator support assembly fixedly attached to the engine stator component; and a stator disposed on a support surface of the stator support structure; and a machine shaft coupled to an end of the shaft via an intermediate shaft member axially extending between the end of the shaft of the propulsion engine and the machine shaft; a bearing support frame extending from the propulsion engine, the bearing support frame including an axial portion extending in an axial direction; a machine bearing radially extending from the axial portion of the bearing support frame to rotatably contact the machine shaft; a seal member axially disposed behind the machine bearing, the seal member extending from the axial portion of the bearing support frame to the machine shaft; and a rotor assembly including: a rotor support structure connected to the machine shaft; and a rotor attached to the rotor support structure such that the rotor is disposed radially inward of the stator, wherein at least one of the following: the rotor rotates with the shaft of the propulsion engine via the intermediate shaft member to generate an electrical signal, and the machine receives electrical power from an external source to provide rotational energy to the shaft.

[0086] 18. The electric machine according to any of the preceding clauses, wherein the rotor support structure is connected to the machine shaft on an axially rear side of the generator bearing to facilitate removal of the rotor from the machine shaft.

[0087] 19. The electric machine according to any of the preceding clauses, further comprising a separating device attached to the propulsion engine, the separating device positioned to axially overlap with the intermediate shaft member to separate the intermediate shaft member.

[0088] 20. The electric machine according to any of the preceding clauses, further comprising a seal extending between the bearing support frame and the machine shaft, the seal fluidically isolating the machine bearing from a bearing of the propulsion engine.

[0089] 21. A motor, comprising: a stator assembly, the stator assembly being coupled to an engine stator component of a propulsion engine, the stator assembly including: a stator support assembly fixedly attached to the engine stator component; and a stator disposed on a support surface of the stator support structure; and a motor shaft coupled to an end of the shaft of the propulsion engine via an intermediate shaft member, the intermediate shaft member axially extending between the end of the shaft and the motor shaft; a bearing support frame extending from the propulsion engine, the bearing support frame and the motor shaft defining a bearing cavity therebetween; a first motor bearing and a second motor bearing radially extending from the bearing support frame for rotatably contacting the motor shaft; a seal member axially disposed behind the motor bearing, the seal member extending from the bearing support frame to the motor shaft; a rotor support structure connected to the motor shaft; and a rotor attached to the rotor support structure, wherein the rotor rotates with the motor shaft to exchange energy with the shaft of the propulsion engine.

[0090] 22. The motor according to any of the preceding clauses, wherein: the bearing cavity is defined by the bearing support frame and the motor shaft together, and an engine bearing of the propulsion engine is disposed within the bearing cavity.

[0091] 23. The motor according to any of the preceding clauses, further comprising: an oil supply line extending through the bearing support frame into a common reservoir at least partially defined between the bearing support frame and the motor shaft; a first oil nozzle extending from the oil supply line and disposed adjacent to the motor bearing; and a second oil nozzle extending from the oil supply line and disposed adjacent to the engine bearing.

[0092] 24. The motor according to any of the preceding clauses, wherein: the stator assembly includes stator support arms connected to the engine stator component via an axial portion of the bearing support frame; and the oil supply line extends through the axial portion of the bearing support frame into the common reservoir.

[0093] 25. The motor according to any of the preceding clauses, further comprising an engine bearing support arm connected to the second engine stator component, the engine bearing support arm and the shaft of the propulsion engine together defining an engine bearing cavity.

[0094] 26. The electric machine according to any of the preceding clauses further includes a first sealing member and a second sealing member, and the first sealing member and the second sealing member extend between the bearing support frame and the electric machine shaft to seal the bearing cavity.

[0095] 27. The electric machine according to any of the preceding clauses further includes: a first oil supply line that extends through the bearing support frame into the bearing cavity; and a second oil supply line that extends into the engine bearing cavity.

[0096] 28. The electric machine according to any of the preceding clauses further includes a separation device attached to the propulsion engine, and the separation device axially overlaps with the intermediate shaft member such that the separation device separates the intermediate shaft member when activated.

[0097] 29. The electric machine according to any of the preceding clauses, wherein the intermediate shaft member allows the electric machine shaft to move in the axial direction and the radial direction relative to the shaft of the propulsion engine.

[0098] 30. The electric machine according to any of the preceding clauses, wherein the intermediate shaft includes a sleeve shaft, and the sleeve shaft includes a first spline provided at its first end and a second spline provided at its second end, and the first spline and the second spline are inserted into openings at the ends of the shaft of the propulsion engine and the electric machine shaft to allow the electric machine shaft to move in the axial direction and the radial direction.

[0099] 31. The electric machine according to any of the preceding clauses, wherein the entire rotor and the entire rotor support structure are disposed radially inside the stator assembly.

[0100] 32. The electric machine according to any of the preceding clauses, wherein the rotor support structure is connected to the end of the electric machine shaft by a removable connection such that the rotor support structure and the rotor can be independently removed from the propulsion engine.

[0101] 33. The electric machine according to any of the preceding clauses, wherein the intermediate shaft includes a shear section configured to separate when subjected to a predetermined shear load.

[0102] 34. A propulsion engine, comprising: a core section that generates exhaust gas traveling in an axial direction; a turbine section coupled to a shaft, wherein the turbine section receives the exhaust gas and generates mechanical energy to rotate the shaft; a turbine frame attached to the turbine section, the turbine frame including: a housing coupled to the turbine section; and an inner hub that supports the shaft via a bearing assembly including an engine bearing that supports the shaft; and an electric machine including: a stator assembly including a stator support assembly attached to the inner hub and a stator attached to the stator support structure; an electric machine shaft coupled to an end of the shaft via an intermediate shaft member that axially extends between the end of the shaft and the electric machine shaft; a bearing support frame attached to the inner hub and radially inwardly extending therefrom to define a bearing cavity extending between the bearing support frame and the electric machine shaft; an electric machine bearing radially extending from the bearing support frame to rotatably contact the electric machine shaft; and a rotor assembly including: a rotor support structure connected to the electric machine shaft; and a rotor attached to the rotor support structure and extending radially inwardly of the stator, wherein the rotor rotates with the shaft via the intermediate shaft member to exchange energy with the shaft.

[0103] 35. The propulsion engine according to any of the preceding clauses, wherein: the turbine frame further includes a plurality of struts extending between the housing and the inner hub, and at least one of the plurality of struts defines an internal cavity having a cooling duct disposed therein.

[0104] 36. The propulsion engine according to any of the preceding clauses, wherein the electric machine further includes a cooling system including a stator manifold to supply coolant from a coolant source to the stator assembly and the rotor assembly.

[0105] 37. The propulsion engine according to any of the preceding clauses, wherein the intermediate shaft member and the electric machine shaft are integrated components.

[0106] 38. The propulsion engine according to any of the preceding clauses, further including a separation device axially overlapping the intermediate shaft member such that the separation device separates the intermediate shaft member when activated.

[0107] 39. The propulsion engine according to any of the preceding clauses, wherein the intermediate shaft member allows movement of the electric machine shaft relative to the shaft of the propulsion engine in both axial and radial directions.

[0108] 40. The propulsion engine according to any of the preceding clauses further includes a sealing member that extends between the bearing support frame and the motor shaft to seal the bearing cavity.

[0109] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Accordingly, this specification is intended to cover modifications and variations of the various embodiments described herein provided that such modifications and variations fall within the scope of the appended claims and their equivalents.

Claims

1. A motor, characterized in that, Comprising: A stator assembly, the stator assembly being coupled to an engine stator component of a propulsion engine, the stator assembly including: A stator support assembly, the stator support assembly being fixedly attached to the engine stator component; and A stator, the stator being disposed on a support surface of the stator support structure; and A motor shaft, the motor shaft being coupled to an end of the shaft of the propulsion engine via an intermediate shaft member, the intermediate shaft member axially extending between the end of the shaft and the motor shaft; A bearing support frame, the bearing support frame extending from the propulsion engine, the bearing support frame and the motor shaft defining a bearing cavity therebetween; A first motor bearing and a second motor bearing, the first motor bearing and the second motor bearing radially extending from the bearing support frame to rotatably contact the motor shaft; A sealing member, the sealing member being axially disposed rearward of the motor bearing, the sealing member extending from the bearing support frame to the motor shaft; A rotor support structure, the rotor support structure being connected to the motor shaft; and A rotor, the rotor being attached to the rotor support structure, wherein the rotor rotates with the motor shaft to exchange energy with the shaft of the propulsion engine, wherein the entire rotor and the entire rotor support structure are disposed radially inward of the stator assembly.

2. The motor according to claim 1, characterized in that, Wherein: The bearing cavity is defined by the bearing support frame and the motor shaft together, and An engine bearing of the propulsion engine is disposed within the bearing cavity.

3. The motor according to claim 2, characterized in that, Further comprising: An oil supply line, the oil supply line extending through the bearing support frame into a common reservoir at least partially defined between the bearing support frame and the motor shaft; A first oil nozzle, the first oil nozzle extending from the oil supply line and being disposed adjacent to the motor bearing; and A second oil nozzle, the second oil nozzle extending from the oil supply line and being disposed adjacent to the engine bearing.

4. The motor according to claim 3, characterized in that, Wherein: The stator assembly includes stator support arms, the stator support arms being connected to the engine stator component via an axial portion of the bearing support frame; and The oil supply line extends through the axial portion of the bearing support frame into the common reservoir.

5. The motor according to claim 1, characterized in that, Further comprising an engine bearing support arm connected to the second engine stator component, the engine bearing support arm and the shaft of the propulsion engine defining an engine bearing cavity therebetween.

6. The motor according to claim 5, characterized in that, Further comprising a first sealing member and a second sealing member, the first sealing member and the second sealing member extending between the bearing support frame and the motor shaft to seal the bearing cavity.

7. The motor according to claim 6, characterized in that, Further comprising: A first oil supply line, the first oil supply line extending through the bearing support frame into the bearing cavity; And A second oil supply line, the second oil supply line extending into the engine bearing cavity.

8. The motor according to claim 1, characterized in that, Further comprising a separation device attached to the propulsion engine, the separation device being axially overlapped with the intermediate shaft member such that the separation device separates the intermediate shaft member upon activation.

9. The motor according to claim 1, characterized in that, The intermediate shaft member allows movement of the motor shaft relative to the shaft of the propulsion engine in both the axial and radial directions.

10. The motor according to claim 9, characterized in that, The intermediate shaft includes a sleeve shaft having a first spline provided at its first end and a second spline provided at its second end, wherein the first spline and the second spline are inserted into openings at the ends of the shaft of the propulsion engine and the motor shaft to allow movement of the motor shaft in the axial and radial directions.

11. The motor according to claim 1, characterized in that, The rotor support structure is connected to the end of the motor shaft by a removable connection such that the rotor support structure and the rotor can be removed independently from the propulsion engine.

12. The motor according to claim 1, wherein, The intermediate shaft includes a shear section configured to separate when subjected to a predetermined shear load.

13. A propulsion engine, wherein, Comprising: A core section that generates exhaust gas traveling in the axial direction; A turbine section coupled to a shaft, wherein the turbine section receives the exhaust gas and generates mechanical energy to rotate the shaft; A turbine frame attached to the turbine section, the turbine frame including: A housing coupled to the turbine section; and An inner hub that supports the shaft via a bearing assembly including an engine bearing that supports the shaft; and A motor including: A stator assembly including a stator support assembly attached to the inner hub and a stator attached to the stator support structure; A motor shaft coupled to the end of the shaft via an intermediate shaft member that axially extends between the end of the shaft and the motor shaft; A bearing support frame attached to the inner hub and radially inwardly extending therefrom to define a bearing cavity extending between the bearing support frame and the motor shaft; A motor bearing radially extending from the bearing support frame to rotatably contact the motor shaft; and A rotor assembly including: A rotor support structure connected to the motor shaft; and A rotor attached to the rotor support structure and extending radially inside the stator, wherein the rotor rotates with the shaft via the intermediate shaft member to exchange energy with the shaft, and wherein the entire rotor and the entire rotor support structure are disposed radially inside the stator assembly.

14. The propulsion engine according to claim 13, wherein, Wherein: The turbine frame further includes a plurality of struts extending between the housing and the inner hub, and At least one of the plurality of struts defines an internal cavity having a cooling duct disposed therein.

15. The propulsion engine according to claim 14, wherein, The motor further includes a cooling system including a stator manifold to supply coolant from a coolant source to the stator assembly and the rotor assembly.

16. The propulsion engine according to claim 13, wherein, The intermediate shaft member and the motor shaft are integrated components.

17. The propulsion engine according to claim 13, wherein, Further comprising a separation device that axially overlaps the intermediate shaft member such that the separation device separates the intermediate shaft member when activated.

18. The propulsion engine according to claim 13, wherein, Wherein the intermediate shaft member allows movement of the motor shaft relative to the shaft of the propulsion engine in both the axial direction and the radial direction.

19. The propulsion engine according to claim 13, wherein, Further comprising a sealing member that extends between the bearing support frame and the motor shaft to seal the bearing cavity.

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