Fan stationary blade retaining structure of open rotor engine

Abstract

The invention relates to the field of aero-engines, in particular to a fan stationary blade retaining structure of an open rotor engine. The fan stationary blade retaining structure is positioned between the fan blade handle and the stationary blade hub and comprises a magnetic suspension spherical joint; the magnetic suspension spherical joint comprises a spherical joint inner shell, a spherical joint outer shell, a limiting structure and an electromagnetic force adjusting device. The tail end of a blade handle of the fan stationary blade is fixedly connected with a spherical joint inner shell of the magnetic suspension spherical joint, and a spherical joint outer shell is installed in a corresponding installation cavity in the stationary blade hub and then fixed to the intermediate case. The limiting structure is arranged between the spherical joint inner shell and the spherical joint outer shell along the axis of the blade handle, and a local mechanical weak part is arranged on the limiting structure. The limiting structure between the spherical joint inner shell and the spherical joint outer shell can decouple the fan stationary blade and the intermediate case, impact and vibration loads transmitted to the intermediate case are reduced, and it is guaranteed that the intermediate case still has enough structural safety after being subjected to large impact loads.

Description

Technical Field

[0001] The invention relates to the field of aviation engines, and in particular to a fan stator blade retaining structure of an open rotor engine. Background Art

[0002] The open rotor engine is a new type of engine between the turboprop engine and the turbofan engine.

[0003] A turboprop engine, also known as a turboprop engine, uses the power generated by the rotation of the propeller as the power for the aircraft to move forward.

[0004] A turbofan engine, also known as an internal-external bypass engine, is a gas turbine engine that generates thrust by the external bypass airflow formed by one or more stages of fans installed on the compressor and the gas discharged from the internal nozzle or the internal and external bypass airflows mixed and discharged. It operates on the following principle: the central gas turbine core drives the bypass fan, which is located at a radial position between the engine nacelle and the engine core. With this type of construction, the engine is generally limited in the allowable size of the bypass fan, because increasing the size of the fan correspondingly increases the size and weight of the nacelle.

[0005] Open rotor engines, also known as unducted engines, operate on the principle of positioning the bypass fan outside the nacelle. This allows the use of larger rotor blades that can act on a larger volume of air than conventional turbofan engines, potentially improving propulsive efficiency over conventional turbofan engine designs.

[0006] Compared with turboprop engines and turbofan engines, open rotor engines can achieve an ultra-large bypass ratio (30 to 90), have higher propulsion efficiency than turbofan engines under high subsonic cruise conditions, and have a fuel consumption rate that is 25% lower than that of current engines in service. It is one of the important technical approaches to achieving green aviation.

[0007] In order to improve the efficiency of the open rotor engine, the fan blades are adjusted to a matching angle by the variable pitch system according to the flight conditions. The open fan blades rotate around the engine axis, so that the airflow leaving the fan blades has not only an axial velocity, but also a circumferential rotational velocity. The circumferential rotation of the airflow is not conducive to the generation of thrust and causes energy loss. Therefore, a set of stationary blades can be installed at a certain distance behind the single row of rotating blades to form a double-row rotating and stationary open fan. The second row of stationary blades is used to correct the vortex from the front row of moving blades and twist the exhaust vortex to the axial direction, thereby improving efficiency. For example, patent document CN112664280A discloses a single unducted rotor engine, such as Figure 1As shown, the engine 10 is in the form of an open rotor propulsion system and has a rotor assembly 12, which includes an array of rotor blades 16 arranged around a central longitudinal axis 14 of the engine 10; a non-rotating guide vane assembly 18 positioned behind the rotor assembly 12, which includes an array of guide vanes 20 also arranged around the central axis 14; the rotor assembly 12 is provided with a pitch changing mechanism 58 for rotating the rotor blades 16 around their respective pitch axes 60, and the guide vane assembly 18 is provided with a pitch changing mechanism 62 for rotating the guide vanes 20 around their respective pitch axes 64.

[0008] The fan blade's petiole is mounted on the hub through a retaining structure. In the traditional scheme, the open fan stator is installed in the corresponding stator hub hole on the intermediate casing through a rigid retaining structure (such as the way the petiole cooperates with the bearing). The fan blade can rotate under the torque drive of the variable pitch system at the end of the petiole, thereby realizing the function of adjusting the fan blade pitch angle. During engine operation, the open fan stator retaining structure needs to bear the blade's own load, the aerodynamic load, and the variable pitch drive load, and transmit these loads through the stator hub to the intermediate casing and even the mounting system.

[0009] Since the fan blades of an open rotor engine are located outside and are not surrounded by an external casing, there is a risk of accidents such as bird strikes. Airworthiness clauses require that open rotor engines maintain sufficient structural integrity after being hit by a bird or other accident to ensure flight safety during the continuous rotation phase (which may be up to 180 minutes) until safe return. After a fan stator blade is hit by a bird or other accident, the impact load will be transmitted through the retaining structure to the intermediate casing where it is located, and then to the installation system and even the aircraft. In addition, the fan component of an open rotor engine does not have an external casing. Damage to the stator blades caused by a bird strike can easily cause flow field turbulence. The damaged stator blades are excited by the complex flow field and the vibration is intensified. The vibration transmitted to the intermediate casing and the installation system also increases, which may endanger the safety of the engine during the continuous rotation phase.

[0010] Therefore, there is a need for a stationary blade retaining structure that can effectively reduce the impact and vibration loads transmitted to the intermediate casing after the blade is impacted or even damaged by foreign objects. Summary of the invention

[0011] The present invention provides a fan stator blade holding structure for an open rotor engine. The introduction of a magnetic suspension spherical joint helps to stably install and reliably operate the fan stator blades. The limiting structure between the spherical joint inner shell and the spherical joint outer shell of the magnetic suspension spherical joint can decouple the fan stator blades from the intermediate casing, reduce the impact and vibration load transmitted to the intermediate casing, and ensure that after being subjected to a large impact load, the intermediate casing still has sufficient structural safety to ensure flight safety. In addition, the magnetic suspension characteristics of the holding structure can reduce the noise and wear caused by mechanical friction, and also make the fan structure more compact and lightweight, which is conducive to the miniaturization and lightweight design of the fan.

[0012] To achieve the above object, the technical solution adopted by the present invention is: A fan stator blade holding structure of an open rotor engine, the open rotor engine comprising a splitter ring assembly, an intermediate casing, a fan stator blade and a stator blade hub, the blade handle of the fan stator blade is connected to the stator blade hub through a blade holding structure, and the stator blade hub is fixed to the intermediate casing; the fan stator blade holding structure is located between the blade handle and the stator blade hub, and comprises a magnetic suspension spherical joint; the magnetic suspension spherical joint comprises a spherical joint inner shell, a spherical joint outer shell, a limiting structure and an electromagnetic force regulating device; the spherical joint inner shell is arranged inside the spherical joint outer shell, and the spherical joint inner shell is connected to the There is a gap between the spherical joint shells; the end of the petiole of the fan stator blade is fixedly connected to the spherical joint inner shell of the magnetic levitation spherical joint, and the spherical joint shell is installed in the corresponding installation cavity on the stator blade hub, and then fixed on the intermediate casing; the limiting structure is arranged on the side of the spherical joint inner shell and the spherical joint shell away from the petiole, and is arranged between the spherical joint inner shell and the spherical joint shell along the petiole axis, and there is a local mechanical weak part on the limiting structure; the electromagnetic force adjustment device is used to control the electromagnetic force applied to the spherical joint inner shell.

[0013] Furthermore, the spherical joint inner shell and the spherical joint outer shell are provided with corresponding mounting holes along the axis of the petiole on one side away from the petiole, and the two ends of the limiting structure are respectively installed in the mounting holes on the spherical joint inner shell and the spherical joint outer shell, and the minimum cross-section of the local mechanical weak part on the limiting structure is located in the gap part between the spherical joint inner shell and the spherical joint outer shell.

[0014] Furthermore, the outer diameters of the two ends of the limiting structure are smaller than or equal to the inner diameters of the mounting holes on the spherical joint inner shell and the spherical joint outer shell.

[0015] Furthermore, the limiting structure is a pin with a necked section.

[0016] Furthermore, the local mechanical weak portion of the limiting structure is an annular groove, the cross-sectional shape of the annular groove is V-shaped, and the diameter of the local mechanical weak portion in the middle of the limiting structure is smaller than the diameter at both ends of the limiting structure, and the ratio of the minimum diameter of the local mechanical weak portion to the diameter at both ends of the limiting structure is 1:3 to 1:5.

[0017] Furthermore, an electromagnetic force regulating device is arranged on the outer shell of the spherical joint, and the electromagnetic force applied to the inner shell of the spherical joint is controlled by the electromagnetic force regulating device; the electromagnetic force regulating device is connected to the magnetic levitation control system, and the magnetic levitation control system has an active control function, which can adjust the current and magnetic field strength of the electromagnetic force regulating device in time according to the vibration and impact conditions monitored in real time, so as to realize the control of the suspension state of the magnetic levitation spherical joint.

[0018] Furthermore, an electromagnetic coil is provided on the spherical joint outer shell, and the spherical joint inner shell is formed of a magnetic material, and the electromagnetic force regulating device controls the electromagnetic force applied to the spherical joint inner shell by adjusting the current of the electromagnetic coil on the spherical joint outer shell; or, electromagnetic coils are provided on both the spherical joint outer shell and the spherical joint inner shell, and the electromagnetic force regulating device controls the electromagnetic force applied to the spherical joint inner shell by adjusting the current of the electromagnetic coil on the spherical joint outer shell and the electromagnetic coil on the spherical joint inner shell.

[0019] Furthermore, the spherical joint inner shell includes a spherical body at the bottom and a connecting seat at the top, and a connecting flange is provided at the end of the petiole away from the fan stator blade; a plurality of connecting holes are evenly provided on the outer periphery of the connecting seat and the connecting flange, and connecting bolts pass through the corresponding connecting holes on the connecting seat and the connecting flange, thereby fixing the spherical joint inner shell to the petiole.

[0020] Furthermore, the spherical body at the lower part of the spherical joint inner shell is formed integrally with the connecting seat at the upper part, and the spherical body is a hollow structure or a solid structure.

[0021] Further, in a state where the spherical centers of the spherical joint inner shell and the spherical joint outer shell are aligned, a gap between the spherical joint inner shell and the spherical joint outer shell is 1-10 mm.

[0022] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in that when the fan stator blades are impacted by foreign objects, the impact and vibration loads transmitted to the intermediate casing can be reduced, as follows: (1) The magnetic suspension spherical joint design in the present invention utilizes magnetic suspension technology to make the connection between the fan stator and the intermediate casing no longer a traditional rigid connection, but have a certain degree of flexibility and buffering capacity. This design allows the fan stator to absorb and disperse the disturbance energy through the slight displacement of the spherical joint when the flow field is slightly disturbed, so that the fan stator can be stably installed and operate reliably; (2) When the load exceeds a certain threshold, the limit structure between the inner shell and the outer shell fails at the mechanically weak point. At the same time, the electromagnetic force output by the outer shell is weakened by adjusting the current, reducing the magnetic control of the outer shell on the inner shell, so that the inner and outer surfaces of the spherical joint present a ball joint matching mode, reducing the load transmitted to the intermediate casing and ensuring the safety of the intermediate casing.

[0023] In addition, the magnetic suspension characteristics of the holding structure of the present invention enable the stationary blade to rotate around the blade stalk axis and freely adjust its angle within a certain range to achieve the variable pitch function, and also reduce the noise and wear caused by mechanical friction. The introduction of the magnetic suspension spherical joint also makes the fan structure more compact and lightweight, which is conducive to the miniaturization and lightweight design of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural schematic diagram of the prior art; Figure 2 It is an overall schematic diagram of the fan stator blade holding structure of the open rotor engine of the present invention; Figure 3 It is a schematic diagram of the structure of the magnetic levitation joint of the present invention; Figure 4 It is a schematic diagram of the connection structure between the petiole and the inner shell of the magnetic suspension ball joint of the present invention; Figure 5 It is a structural schematic diagram of the limiting structure of the present invention.

[0026] Reference numerals in the figures: Diverter ring assembly 1; Intermediate Casing 2; Fan stator blade 3; Stationary blade hub 4; Petiole 5; Connecting flange 51; Connecting bolt 52; Spherical joint inner shell 6; Spherical body 61; Connecting seat 62; Ball joint housing 7; Limiting structure 8; annular groove 81; Electromagnetic force regulating device 9; Electromagnetic coil 91; Magnetic levitation control system 10. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0029] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0030] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0031] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the examples can be practiced without these specific details.

[0032] At the same time, in this specification, descriptions involving orientations, such as up, down, left, right, front, back, inside, outside, longitudinal, lateral, vertical, horizontal, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] like Figure 2 As shown, the open rotor engine of the present invention comprises a splitter ring assembly 1, an intermediate casing 2, a fan stator blade 3, and a stator blade hub 4. The blade handle 5 of the fan stator blade 3 is connected to the stator blade hub 4 through a blade holding structure, and the stator blade hub 4 is fixed to the intermediate casing 2. In the open rotor engine, a small part of the gas flowing in from the front row of fan blades passes through the splitter ring assembly 1 and enters the engine interior, while most of the gas flows out after being rectified by the fan stator blade 3 to provide thrust for the engine.

[0034] See also Figure 2 and 3 The fan stator blade holding structure of the present invention is located between the blade handle 5 of the fan stator blade and the blade hub 4, and includes a magnetic suspension spherical joint. The magnetic suspension spherical joint mainly includes a spherical joint inner shell 6, a spherical joint outer shell 7, a limiting structure 8 and an electromagnetic force adjustment device 9. The spherical joint inner shell 6 is arranged inside the spherical joint outer shell 7, and there is a gap between the spherical joint inner shell 6 and the spherical joint outer shell 7. The end of the blade handle 5 of the fan stator blade 3 is fixedly connected to the spherical joint inner shell 6 of the magnetic suspension spherical joint, and the spherical joint outer shell 7 is installed in the corresponding installation cavity on the stator hub 4, and then fixed on the intermediate casing 2.

[0035] The limiting structure 8 is arranged on the side of the spherical joint inner shell 6 and the spherical joint outer shell 7 away from the petiole 5, and is arranged between the spherical joint inner shell 6 and the spherical joint outer shell 7 along the axis of the petiole, and there is a local mechanical weak part on the limiting structure 8. Specifically, the spherical joint inner shell 6 and the spherical joint outer shell 7 are provided with corresponding mounting holes along the axis of the petiole 5 on the side away from the petiole 5, and the two ends of the limiting structure 8 are respectively mounted in the mounting holes on the spherical joint inner shell 6 and the spherical joint outer shell 7, and the minimum cross-section of the local mechanical weak part on the limiting structure 8 is located in the gap between the spherical joint inner shell 6 and the spherical joint outer shell 7. In order to ensure the magnetic suspension between the spherical joint inner shell 6 and the spherical joint outer shell 7, the outer diameters of the two ends of the limiting structure 8 are less than or equal to the inner diameters of the mounting holes on the spherical joint inner shell 6 and the spherical joint outer shell 7.

[0036] Preferably, the limiting structure 8 is a pin with a necked section.

[0037] The electromagnetic force regulating device 9 is arranged on the spherical joint outer shell 7. The electromagnetic force regulating device 9 can control the electromagnetic force applied to the spherical joint inner shell 6, so that the spherical joint inner shell 6 is suspended inside the spherical joint outer shell 7, thereby realizing the contactless suspension of the magnetic suspension spherical joint. The electromagnetic force regulating device 9 is connected to the magnetic suspension control system 10. The magnetic suspension control system 10 has an active control function, and can timely adjust the current and magnetic field strength of the electromagnetic force regulating device 9 according to the vibration and impact conditions monitored in real time, thereby realizing the control of the suspension state of the magnetic suspension spherical joint.

[0038] Furthermore, an electromagnetic coil 91 is provided on the spherical joint outer shell 7 , and the spherical joint inner shell 6 is formed of a magnetic material. The electromagnetic force regulating device 9 controls the electromagnetic force applied to the spherical joint inner shell 6 by adjusting the current of the electromagnetic coil 91 on the spherical joint outer shell 7 .

[0039] Alternatively, an electromagnetic coil 91 is provided on both the spherical joint outer shell 7 and the spherical joint inner shell 6, and the electromagnetic force regulating device 9 controls the electromagnetic force applied to the spherical joint inner shell 6 by adjusting the current of the electromagnetic coil 91 on the spherical joint outer shell 7 and the electromagnetic coil 91 on the spherical joint inner shell 6.

[0040] like Figure 3 , 4 As shown, the spherical joint inner shell 6 includes a spherical body 61 at the bottom and a connecting seat 62 at the top, and a connecting flange 51 is provided at one end of the blade stalk 5 away from the fan stator blade 3. A plurality of connecting holes are evenly provided on the connecting seat 62 and the connecting flange 51, and the connecting bolts 52 pass through the corresponding connecting holes on the connecting seat 62 and the connecting flange 51, thereby fixing the spherical joint inner shell 6 and the blade stalk 5 together.

[0041] Preferably, the spherical body at the lower part of the spherical joint inner shell 6 is formed integrally with the connecting seat at the upper part, and the spherical body is a hollow structure or a solid structure.

[0042] In order to obtain a better magnetic suspension effect, when the spherical centers of the spherical joint inner shell 6 and the spherical joint outer shell 7 are aligned, the gap between the spherical joint inner shell 6 and the spherical joint outer shell 7 is 1-10 mm.

[0043] Further, if Figure 5 As shown, the limiting structure 8 is roughly cylindrical, and a local mechanical weak part is arranged in the middle. The specific form of the local mechanical weak part is an annular groove 81, and the cross-sectional shape of the annular groove is preferably V-shaped, arc-shaped or rectangular. The diameter of the local mechanical weak part in the middle of the limiting structure 8 is smaller than the diameter at both ends of the limiting structure 8, and the ratio of the minimum diameter of the local mechanical weak part to the diameter at both ends of the limiting structure 8 is 1:3 to 1:5.

[0044] Since the end of the petiole 5 of the fan stator blade 3 is fixedly connected to the spherical joint inner shell 6 of the magnetic levitation spherical joint, the spherical joint inner shell 6 bears the self-load of the fan stator blade 3, the aerodynamic load borne by the fan stator blade 3, and the variable pitch drive load of the fan stator blade 3. In the present invention, the variable pitch drive load of the fan stator blade 3 is the electromagnetic force generated by the magnetic levitation spherical joint.

[0045] When the open rotor engine is working normally, due to the constraint of the limit structure 8 between the spherical joint inner shell 6 and the spherical joint outer shell 7, the fan stator 3 can rotate around the axis of the blade handle 5 under the control of the electromagnetic force adjustment device of the spherical joint outer shell 7, thereby realizing the function of adjusting the pitch angle of the fan stator 3 and ensuring the normal operation of the open rotor engine. At this time, the magnetic suspension spherical joint makes the connection between the fan stator 3 and the stator hub 4 no longer a traditional rigid connection, but has a certain flexibility and buffering capacity, which is conducive to the stable operation of the fan stator 3.

[0046] When the impact load transmitted from the fan stator 3 to the spherical joint outer shell 7 through the petiole 5 and the spherical joint inner shell 6 exceeds the set threshold of the limiting structure 8, the limiting structure 8 between the spherical joint inner shell 6 and the spherical joint outer shell 7 will fail at the mechanically weak part and thus break. At this time, due to the structural characteristics of the spherical joint inner shell 6 and the spherical joint outer shell 7, the spherical joint outer shell 7 can still provide sufficient constraints on the spherical joint inner shell 6, thereby ensuring that the petiole 5 will not fly out, so that the fan stator 3 can maintain sufficient structural integrity and ensure continuous flight safety. At this time, the magnetic levitation control system 10 adjusts the current of the electromagnetic coil through the electromagnetic force adjustment device 9 to weaken the output electromagnetic force and reduce the electromagnetic force control of the spherical joint inner shell 6, so that the inner and outer shell surfaces of the spherical joint still present a magnetic levitation ball joint matching mode, and the fan stator can rotate arbitrarily in three directions. Due to the fracture failure of the limiting structure 8 and the reduction of the electromagnetic force applied to the spherical joint inner shell 6, the impact load of the fan stator 3 will be difficult to be transmitted to the spherical joint outer shell 7 through the spherical joint inner shell 6, thereby avoiding the intermediate casing 2 from being subjected to the impact load.

[0047] Through the failure and fracture of the limiting structure 8 in the stator blade retaining structure, on the one hand, the rotation constraint of the fan stator blade 3 at the blade root can be released, so that the fan stator blade 3 can swing with the airflow stimulation, thereby converting most of the energy received by the fan stator blade 3 into the kinetic energy of the fan stator blade 3, reducing the internal energy generated by the fan stator blade 3 and transmitted to the outside; on the other hand, the failure and fracture of the limiting structure 8 and the weak coupling between the spherical joint inner shell 6 and the spherical joint outer shell 7 can weaken the impact and vibration load transmission path between the fan stator blade 3 and the intermediate casing 2, thereby fully ensuring the safety of the intermediate casing.

[0048] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A fan stator blade retaining structure of an open rotor engine, the open rotor engine comprising a splitter ring assembly (1), an intermediate casing (2), a fan stator blade (3) and a stator blade hub (4), a blade handle (5) of the fan stator blade (3) being connected to the stator blade hub (4) via a blade retaining structure, and the stator blade hub (4) being fixed to the intermediate casing (2); Features: The fan stator blade retaining structure is located between the blade handle (5) and the stator blade hub (4), and comprises a magnetic suspension spherical joint; the magnetic suspension spherical joint comprises a spherical joint inner shell (6), a spherical joint outer shell (7), a limiting structure (8) and an electromagnetic force regulating device (9); The spherical joint inner shell (6) is arranged inside the spherical joint outer shell (7), and a gap is provided between the spherical joint inner shell (6) and the spherical joint outer shell (7); the end of the blade handle (5) of the fan stator blade (3) is fixedly connected to the spherical joint inner shell (6) of the magnetic suspension spherical joint, and the spherical joint outer shell (7) is installed in a corresponding installation cavity on the stator blade hub (4); The limiting structure (8) is arranged on a side of the spherical joint inner shell (6) and the spherical joint outer shell (7) away from the petiole (5), and is arranged between the spherical joint inner shell (6) and the spherical joint outer shell (7) along the petiole axis, and a local mechanical weak point is provided on the limiting structure (8); The electromagnetic force regulating device (9) is used to control the electromagnetic force applied to the spherical joint inner shell (6).

2. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: The spherical joint inner shell (6) and the spherical joint outer shell (7) are provided with corresponding mounting holes along the axis of the petiole (5) on a side away from the petiole (5); two ends of the limiting structure (8) are respectively mounted in the mounting holes on the spherical joint inner shell (6) and the spherical joint outer shell (7); and the minimum cross-section of the local mechanically weak part on the limiting structure (8) is located in the gap between the spherical joint inner shell (6) and the spherical joint outer shell (7).

3. The fan stator blade retaining structure of an open rotor engine according to claim 2, characterized in that: The outer diameters of both ends of the limiting structure (8) are smaller than or equal to the inner diameters of the mounting holes on the spherical joint inner shell (6) and the spherical joint outer shell (7).

4. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: The limiting structure (8) is a pin with a necked section.

5. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: The local mechanical weak part of the limiting structure (8) is an annular groove (81), the cross-sectional shape of the annular groove (81) is V-shaped, arc-shaped or rectangular, and the diameter of the local mechanical weak part in the middle of the limiting structure (8) is smaller than the diameters at both ends of the limiting structure (8), and the ratio of the minimum diameter of the local mechanical weak part to the diameters at both ends of the limiting structure (8) is 1:3 to 1:

5.

6. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: The electromagnetic force regulating device (9) is arranged on the spherical joint housing (7); the electromagnetic force regulating device (9) is connected to a magnetic suspension control system (10); the magnetic suspension control system (10) has an active control function and can adjust the current and magnetic field strength of the electromagnetic force regulating device (9) according to vibration and impact conditions monitored in real time, thereby achieving control of the suspension state of the magnetic suspension spherical joint.

7. The fan stator blade retaining structure of an open rotor engine according to claim 6, characterized in that: The spherical joint outer shell (7) is provided with an electromagnetic coil (91), the spherical joint inner shell (6) is formed of a magnetic material, and the electromagnetic force regulating device (9) controls the electromagnetic force applied to the spherical joint inner shell (6) by adjusting the current of the electromagnetic coil (91) on the spherical joint outer shell (7); or, the spherical joint outer shell (7) and the spherical joint inner shell (6) are both provided with an electromagnetic coil (91), and the electromagnetic force regulating device (9) controls the electromagnetic force applied to the spherical joint inner shell (6) by adjusting the current of the electromagnetic coil (91) on the spherical joint outer shell (7) and the electromagnetic coil (91) on the spherical joint inner shell (6).

8. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: The spherical joint inner shell (6) comprises a spherical body (61) at a lower portion and a connecting seat (62) at an upper portion; a connecting flange (51) is provided at one end of the blade stalk (5) away from the fan stator blade (3); a plurality of connecting holes are evenly provided on the periphery of the connecting seat (62) and the connecting flange (51); connecting bolts (52) pass through corresponding connecting holes on the connecting seat (62) and the connecting flange (51), thereby fixing the spherical joint inner shell (6) to the blade stalk (5).

9. The fan stator blade retaining structure of an open rotor engine according to claim 8, characterized in that: The spherical body (61) at the lower part of the spherical joint inner shell (6) and the connecting seat (62) at the upper part are formed integrally, and the spherical body (61) is a hollow structure or a solid structure.

10. The fan stator blade retaining structure of an open rotor engine according to claim 1, characterized in that: When the spherical centers of the spherical joint inner shell (6) and the spherical joint outer shell (7) are aligned, the gap between the spherical joint inner shell (6) and the spherical joint outer shell (7) is 1-10 mm.

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