Built-in generator structure of aero-engine

Abstract

The invention discloses a built-in generator structure of an aero-engine. A motor rotor is installed on a rotating part of a closed area and connected with a high-pressure rotor shaft. A central transmission structure of the engine is omitted, an external starter and a transmission structure of the external starter are omitted, the weight of the transmission structure and the weight of the engine can be greatly reduced in cooperation with multiple electric accessories, and the purpose of internally arranging the starter is achieved by adopting the mode of internally arranging the axial flux motor and the mode of directly or indirectly connecting the motor rotor and the core crankshaft. The motor has the characteristics of high power density, efficient cooling, easy realization and the like, and can greatly reduce the weight of a transmission structure and an engine by cooperating with multiple electric accessories.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine structural design technology, specifically relating to an aero-engine built-in generator structure. Background Technology

[0002] Currently, all aero engines use an external starter to transmit power to the engine core rotor via gears. For twin-shaft engines, the core rotor is typically a high-pressure rotor. After the engine completes the starting process, the core rotor then outputs power to a generator on the engine accessory housing via gears. There are currently two main engine starting and power generation structures: one is an externally mounted integrated starter and generator motor, and the other is an air or gas turbine starter motor plus a DC (or AC) generator. Both structures require a complex mechanical transmission system to transmit power from the engine core to the outside.

[0003] With the increase in electric motor power density, electric motors adapted to high power and high speed are capable of being used inside the casing of aero engines, especially axial flux motors, which are inherently suitable for use inside the intermediate casing of engines with limited axial dimensions but ample radial dimensions. Summary of the Invention

[0004] To address the aforementioned problems, this invention aims to provide a structure for an aircraft engine to integrate a generator.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a generator structure built into an aircraft engine, including an axial flux motor disposed inside an intermediate casing.

[0006] The axial flux motor includes a motor stator and a motor rotor;

[0007] The intermediate casing includes an inner casing, a low-pressure rotor bearing support casing, a low-pressure rotor bearing, a high-pressure rotor bearing forming a closed area casing part, and a closed area rotating part consisting of a low-pressure shaft, a turbine shaft, and a high-pressure rotor shaft.

[0008] The motor stator is mounted on the enclosed housing portion, and the motor rotor is mounted on the enclosed rotating portion and connected to the high-voltage rotor shaft.

[0009] Furthermore, the intermediate casing includes an inner casing, a low-pressure rotor bearing support casing connected to the inner casing, a low-pressure rotor bearing mounted on the low-pressure rotor bearing support casing, a low-pressure shaft connected to the low-pressure rotor bearing, a turbine shaft connected to the low-pressure shaft, a high-pressure rotor shaft connected to the turbine shaft, and a high-pressure rotor bearing mounted on the high-pressure rotor shaft.

[0010] Furthermore, the rotor and stator of the axial flux motor are connected in series. The axial layout includes, but is not limited to, a single rotor with two stators, two rotors with a single stator, and two rotors with two stators. The number of rotors and stators is determined by the axial dimensions of the internal space of the intermediate casing and the generator power.

[0011] Furthermore, the motor rotor includes a disc body and permanent magnets evenly distributed around the outer edge of the disc body, which are connected by tenons, and radial cooling holes are designed on the disc body.

[0012] Furthermore, there is a gap A between the motor stator and the motor rotor, and the gap A does not exceed 3mm.

[0013] Furthermore, the mounting edge of the motor stator is directly connected to the inner casing or the low-pressure rotor bearing support casing, or indirectly connected to the inner casing or the low-pressure rotor bearing support casing through a support mechanism.

[0014] The motor rotor is directly connected to the high-voltage rotor shaft or indirectly connected to the high-voltage rotor shaft through a support structure.

[0015] Furthermore, the support structure includes an intermediate shaft, a first bearing, and a second bearing. The inner casing is also connected to the first casing and the second casing. The first bearing is disposed on the first casing, and the second bearing is disposed on the second casing.

[0016] Furthermore, space is reserved inside the intermediate casing for installing a phase controller.

[0017] Furthermore, a support plate is radially arranged in the internal area of ​​the intermediate casing, and the support plate has a hollow structure.

[0018] Compared with the prior art, the present invention has the following advantages: The present invention eliminates the central transmission structure of the engine and the external starter and its transmission structure. With the addition of multiple electric accessories, the transmission structure and engine weight can be greatly reduced. The purpose of the built-in starter generator is achieved by using a built-in axial flux motor and the direct or indirect connection between the motor rotor and the core shaft. It has the characteristics of high power density, efficient cooling and easy implementation. With the addition of multiple electric accessories, the transmission structure and engine weight can be greatly reduced. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the generator structure built into the aero engine in this invention. Figure 1 ;

[0021] Figure 2 This is a schematic diagram of the generator structure built into the aero engine in this invention. Figure 2 ;

[0022] Figure 3 This is an enlarged view of the stator and rotor of the generator structure built into the aero-engine in this invention;

[0023] In the diagram, 201-intermediate casing; 202-support plate; 203-inner casing; 204-low-pressure rotor bearing support casing; 205-low-pressure rotor bearing; 206-low-pressure shaft; 207-first bearing; 208-phase controller; 209-second bearing; 210-turbine shaft; 211-high-pressure rotor shaft; 212-high-pressure rotor bearing; 213-motor stator (213-1-first stator; 213-2-second stator; 213-3-coil); 214-motor rotor (214-1-cooling hole; 214-2-permanent magnet; 214-3-disc); 215-intermediate shaft; 216-first casing; 217-second stator casing; 218-second bearing casing; 219-second casing; 220-nozzle. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and conventional means in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0025] Reference Figures 1-3 In order to simplify the accessory drive structure of aero engines and reduce engine weight, the axial flux motor is built into the engine intermediate casing to eliminate the traditional central drive structure of the engine and simplify the accessory drive structure, thereby achieving the weight reduction goal.

[0026] This invention proposes a built-in starter-generator structure for an aero-engine. The starter-generator is located inside the engine's intermediate casing 201, which is an annular enclosed area composed of the following components: an inner casing 203, a low-pressure rotor bearing support casing 204, a low-pressure rotor bearing 205, a low-pressure shaft 206, a turbine shaft 210, a high-pressure rotor shaft 211, and a high-pressure rotor bearing 212, all enclosed within the inner casing 203. The inner casing 203, low-pressure rotor bearing support casing 204, low-pressure rotor bearing 205, and high-pressure rotor bearing 212 form the enclosed casing portion. The low-pressure shaft 206, turbine shaft 210, and high-pressure rotor shaft 211 form the rotating portion of the enclosed area. The built-in motor stator 213 is mounted on the enclosed casing portion, and the motor rotor 214 is directly mounted or mounted on the high-pressure rotor shaft 211 via an intermediate shaft 215, ensuring the same rotational speed as the high-pressure shaft.

[0027] The connection relationship of the motor structure is as follows: An inner casing 203 is mounted on the intermediate casing 201; a low-pressure rotor bearing 205 is mounted on the low-pressure rotor bearing support casing 204; a low-pressure shaft 206 is mounted on the low-pressure rotor bearing 205; and a turbine shaft 210 is splined to the low-pressure shaft 206. The turbine shaft 210 is connected to the high-pressure rotor shaft 211, and a high-pressure rotor bearing 212 is mounted on the turbine shaft 211. The high-pressure rotor bearing 212 is mounted on the inner casing 203. The internal area is radially connected to support plates 202 on the intermediate casing 201. The support plates 202 are hollow structures, and the number of support plates 202 is typically greater than four. Each support plate 202 has a corresponding function based on the wiring or pipelines arranged inside the hollow structure, such as oil inlet / outlet, ventilation, power supply, and signal transmission. The lubricating oil and cables used for generator cooling are transmitted to the outside of the engine through the support plates 202.

[0028] The axial arrangement of the motor rotor 214 and stator 213 can be a series structure such as a single rotor with double stators 213-214-213, a double rotor with a single stator 214-213-214, or a double rotor with double stators 213-214-213-214. The number of rotors and stators is determined according to the axial dimensions of the internal space of the intermediate casing 201 and the required generator power.

[0029] The axial flux motor consists of a stator 213 and a rotor 214. The rotor 214 comprises a disk of permanent magnets 214-2 and a disk body 214-3 that constrains the position of the permanent magnets. The permanent magnets 214-2 are evenly distributed circumferentially on the outer edge of the disk body 214-3 and are connected by tenons. Radial oil holes on the disk body provide coolant to the permanent magnets. The coolant enters from the center of the disk body, is flung out by the centrifugal force generated by the high-speed rotation of the rotor 214, cools the permanent magnets on the rotor, and then splashes onto the corresponding coils on the stator 213. The rotor disk body 214-3 is designed with radial cooling holes 214-1 for cooling the permanent magnets 214-2 mounted on the disk body 214-3. An oil pump delivers lubricating oil of appropriate pressure and flow rate to the cooling holes 214-1 through nozzles 220. Under the action of centrifugal force, the lubricating oil flows radially along the cooling hole 214-1, cools the permanent magnet 214-2, and then sprays out obliquely to cool the coil 213-3 on the motor stator 213.

[0030] The motor stator 213 is directly connected to the inner casing 203 or the low-pressure rotor bearing support casing 204 via a mounting edge, or indirectly connected to the inner casing 203 or the low-pressure rotor bearing support casing 204 via a support structure. The motor rotor 214 is connected to the high-voltage shaft 211 via a spline or directly connected to the high-voltage shaft 211 via a thread. After the mechanical connection is achieved, the motor rotor 214 and the high-voltage shaft 211 rotate at the same speed. In the engine starting function, the motor rotor 214 drives the high-voltage shaft 211 to rotate; in the generator function, the high-voltage shaft 211 drives the motor rotor 214 to rotate.

[0031] If the axial distance between the motor rotor 214 and the high-voltage rotor bearing 212 is close, the motor rotor 214 can be directly fixed on the high-voltage shaft 211. The fixing method is to transmit torque through a spline and tighten it with a nut.

[0032] If the axial distance between the motor rotor 214 and the high-voltage rotor bearing 212 is large, a separate support structure can be designed for the motor rotor 214. Torque transmission between the motor rotor 214 and the high-voltage shaft 211 is achieved through an intermediate shaft 215. The separately designed support structure includes an intermediate shaft 215, a first bearing 207, and a second bearing 209. A first housing 216 and a second housing 219 are also connected to the inner housing 203. The first bearing 207 is mounted on the first housing 216, and the second bearing 209 is mounted on the second housing 219. The second housing 219 is integrally formed by a second stator housing 217 and a second bearing housing 218. The intermediate shaft 215 connects the high-voltage rotor shaft 211 and the second bearing 209. The second bearing 209 is connected to the motor rotor 214. The first bearing 207 connects the motor rotor 214 and the first housing 216. The first housing 216 and the second stator housing 217 are connected to the first stator 213-1 and the second stator 213-2, respectively.

[0033] The motor starting and power generation functions are achieved through mode switching of the controller. If necessary, the design space for the starter-generator phase controller is 208. The phase controller is used to determine the rotation phase of the motor rotor 214, and the phase controller rotor is connected to the motor rotor 214.

[0034] Example 1: The internal axial design space of an engine intermediate casing is 220mm, and the radial design space is R330mm. It adopts a single rotor 214 and dual stator 213 structure, with the dual stator 213 including a first stator 213-1 and a second stator 213-2. The axial distance between the motor rotor 214 and the high-pressure rotor bearing 212 is 150mm. Therefore, a support structure is used to support the motor rotor 214. The support structure includes a first bearing 207 and a second bearing 209, distributed on both sides of the motor rotor 214. The two bearings are of the same type. The first bearing 207 is fixed to the first casing 216. The first casing 216 and the low-pressure rotor bearing support casing 204 are bolted to the inner casing 203. The first casing 216 is designed with a flange for mounting the first stator 213-1, and the second stator 213-2 is mounted on the second stator casing 217. The second stator housing 217 and the second bearing housing 218 are an integral structure that together constitute the second housing 219. The second bearing 209 is mounted on the second bearing housing 218 and is bolted to the inner housing 203.

[0035] The motor rotor 214 and the high-voltage shaft 211 are connected via an intermediate shaft 215. Splines are designed at both ends of the intermediate shaft 215 to transmit torque between the motor rotor 214 and the high-voltage rotor 211. The intermediate shaft 215 is designed with an axial limiting boss to prevent axial movement during operation. The axial limiting of the motor rotor 214 is secured by a second bearing 209 and an end-face nut. The nut is on the motor rotor 214, and its end face contacts the second bearing 209.

[0036] The motor rotor 214 is designed with radial cooling holes 214-1, and cooling is achieved using lubricating oil. An oil pump delivers lubricating oil at appropriate pressure and flow rate through nozzles 220 to the cooling holes 214-1. Under centrifugal force, the lubricating oil flows radially along the cooling holes 214-1, cooling the permanent magnets 214-2 before being obliquely ejected to cool the coils 213-3 on the motor stator 213. The motor rotor 214 consists of a disc 214-3 and permanent magnets 214-2. The cooling holes 214-1 are located on the disc 214-3, and the permanent magnets 214-2 are evenly distributed circumferentially on the outer edge of the disc 214-3, totaling 72 pieces. The permanent magnets 214-2 and the disc 214-3 are fitted with dovetail tenons with an interference fit of 0.015mm to 0.025mm. The coils 213-2 have a helical structure, with 72 coils evenly distributed axially on one side of the stator.

[0037] The distance A between the motor rotor 214 and stator 213 ranges from 1.5mm to 2mm.

[0038] The above provides a detailed description of the built-in generator structure for an aero-engine provided by this invention. Specific examples have been used to illustrate the structure and working principle of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention.

Claims

1. A generator structure built into an aircraft engine, characterized in that: Including an axial flux motor disposed inside the intermediate housing (201), The axial flux motor includes a motor stator (213) and a motor rotor (214); The intermediate casing (201) includes an enclosed area casing part consisting of an inner casing (203), a low-pressure rotor bearing support casing (204), a low-pressure rotor bearing (205), and a high-pressure rotor bearing (212), and an enclosed area rotating part consisting of a low-pressure shaft (206), a turbine shaft (210), and a high-pressure rotor shaft (211); The motor stator (213) is mounted on the enclosed area casing portion, and the motor rotor (214) is mounted on the enclosed area rotating portion and connected to the high-voltage rotor shaft (211).

2. The aero-engine built-in generator structure according to claim 1, characterized in that: The intermediate casing (201) includes an inner casing (203), a low-pressure rotor bearing support casing (204) connected to the inner casing (203), a low-pressure rotor bearing (205) mounted on the low-pressure rotor bearing support casing (204), a low-pressure shaft (206) connected to the low-pressure rotor bearing (205), a turbine shaft (210) connected to the low-pressure shaft (206), a high-pressure rotor shaft (211) connected to the turbine shaft (210), and a high-pressure rotor bearing (212) mounted on the high-pressure rotor shaft (211).

3. The aero-engine built-in generator structure according to claim 1, characterized in that: The motor rotor (214) and motor stator (213) of the axial flux motor are connected in series. The axial layout includes, but is not limited to, single rotor with double stator, double rotor with single stator, and double rotor with double stator. The number of motor rotors (214) and motor stators (213) is determined according to the axial dimensions of the internal space of the intermediate casing (201) and the generator power.

4. The aero-engine built-in generator structure according to claim 3, characterized in that: The motor rotor (214) includes a disc (214-3) and permanent magnets (214-2) evenly distributed around the outer edge of the disc (214-3). The two are connected by tenons, and radial cooling holes (214-1) are designed on the disc (214-3).

5. The aero-engine built-in generator structure according to claim 3, characterized in that: There is a gap A between the motor stator (213) and the motor rotor (214), and the gap A does not exceed 3mm.

6. The aero-engine built-in generator structure according to claim 1, characterized in that: The mounting edge of the motor stator (213) is directly connected to the inner casing (203) or the low-pressure rotor bearing support casing (204) or indirectly connected to the inner casing (203) or the low-pressure rotor bearing support casing (204) through a support mechanism. The motor rotor (214) is directly connected to the high-voltage rotor shaft (211) or indirectly connected to the high-voltage rotor shaft (211) through a support structure.

7. The aero-engine built-in generator structure according to claim 6, characterized in that: The support structure includes an intermediate shaft (215), a first bearing (207) and a second bearing (209). The inner casing (203) is also connected to a first casing (216) and a second casing (219). The first bearing (207) is disposed on the first casing (216) and the second bearing (209) is disposed on the second casing (219).

8. The aero-engine built-in generator structure according to claim 1, characterized in that: There is also space reserved inside the intermediate housing (201) for the installation of the phase controller (208).

9. The aero-engine built-in generator structure according to claim 1, characterized in that: The intermediate casing (201) has a support plate (202) radially arranged in the internal area, and the support plate (202) has a hollow structure.

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