A fan stator blade retaining structure for an open rotor engine

Abstract

The present invention relates to the field of aeroengines, and particularly to a fan stator blade retaining structure of an open rotor engine. The fan stator blade retaining structure is located between the fan blade shank and the stator blade hub, and includes a magnetic levitation spherical joint; the magnetic levitation spherical joint includes a spherical joint inner shell, a spherical joint outer shell, a limiting structure and an electromagnetic force adjusting device; the end of the blade shank of the fan stator blade is fixedly connected to the spherical joint inner shell of the magnetic levitation spherical joint, and the spherical joint outer shell is installed in a corresponding installation cavity on the stator blade hub and is thus fixed on the intermediate casing; the limiting structure is arranged along the axis of the blade shank between the spherical joint inner shell and the spherical joint outer shell, and there is a locally mechanically weak part on the limiting structure. The limiting structure between the spherical joint inner shell and the spherical joint outer shell in the present invention can decouple the fan stator blade from the intermediate casing, reduce the impact and vibration loads transmitted to the intermediate casing, and ensure that the intermediate casing still has sufficient structural safety after being subjected to large impact loads.

Description

Technical Field

[0001] The present invention relates to the field of aero-engines, and particularly to a fan stator blade holding structure of an open rotor engine. Background Art

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

[0003] A turboprop engine, also known as a turbo-propeller engine, uses the force generated when the propeller rotates as the power for the aircraft to move forward.

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

[0005] An open rotor engine, also known as a ducted fan engine, operates based on the principle of positioning the bypass fan outside the engine nacelle. Compared with traditional turbofan engines, this allows the use of larger rotor blades that can act on a larger amount of air, potentially improving the propulsion efficiency compared to conventional turbofan engine designs.

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

[0007] To improve the efficiency of open rotor engines, the fan blades are adjusted to a matching angle by a pitch control system according to the flight conditions. The open fan rotor blades rotate around the engine axis, so that the airflow leaving the fan rotor blades has not only an axial velocity but also a circumferential rotational velocity. The circumferential rotation of the airflow is not conducive to generating thrust and causes energy loss. Therefore, a set of stator blades can be installed at a certain distance after a single row of rotating blades to form a double-row rotating-stator configuration open fan. The second row of stator blades corrects the eddy current from the front row of rotor blades and twists the exhaust eddy current along the axis direction, thereby improving the efficiency. For example, patent document CN112664280A discloses a single ducted fan 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. The rotor assembly 12 includes an array of rotor blades 16 arranged around the central longitudinal axis 14 of the engine 10; a non-rotating stator vane assembly 18 positioned behind the rotor assembly 12, which includes an array of stator vanes 20 also disposed around the central axis 14; the rotor assembly 12 is provided with a pitch changing mechanism 58 for rotating the rotor blades 16 about their respective pitch axes 60, and the stator vane assembly 18 is provided with a pitch changing mechanism 62 for rotating the stator vanes 20 about their respective pitch axes 64.

[0008] The shanks of the fan blades are mounted on the hub through a retaining structure. In the traditional solution, the open fan stator vanes are mounted in the corresponding stator vane hub holes of the intermediate case through a rigid retaining structure (such as the way of the cooperation between the shank and the bearing). The fan blades can rotate under the torque of the pitch changing system at the end of the shank, realizing the function of adjusting the pitch angle of the fan blades. During the operation of the engine, the retaining structure of the open fan stator vanes needs to bear the self-load of the blades, the aerodynamic load received, and the pitch changing driving load, and transfer these loads to the intermediate case where they are located and even the installation system through the stator vane hub.

[0009] Since the fan blades of the open rotor engine are located outside and there is no outer case to enclose them, there is a risk of being hit by a bird or other accidents. The airworthiness regulations require that the open rotor engine still maintain sufficient structural integrity after being hit by a bird or other accidents, ensuring the flight safety during the continuous rotation stage (which may be up to 180 minutes) until a safe return. After the open fan stator vanes are hit by a bird or other accidents, the impact load will be transmitted to the intermediate case where they are located through the retaining structure, and then transmitted to the installation system and even the aircraft. In addition, the fan components of the open rotor engine do not have an outer case, and the damage of the stator vanes caused by a bird strike is likely to cause the flow field to be disordered. The damaged stator vanes vibrate more violently under the excitation of the complex flow field, and the vibration transmitted to the intermediate case and the installation system also increases accordingly, which may endanger the safety of the engine during the continuous rotation stage.

[0010] Therefore, a stator vane retaining structure is needed that can effectively reduce the impact and vibration loads transmitted to the intermediate case after the blade is impacted or damaged by foreign objects. Summary of the Invention

[0011] The present invention provides a fan stator blade retaining structure for an open rotor engine. By introducing a magnetic levitation spherical joint, it helps to stably install and reliably operate the fan stator blade. The limiting structure between the inner spherical joint shell and the outer spherical joint shell of the magnetic levitation spherical joint can decouple the fan stator blade from the intermediate casing, reducing the impact and vibration loads transmitted to the intermediate casing, ensuring that the intermediate casing still has sufficient structural safety after suffering large impact loads and guaranteeing flight safety. In addition, the magnetic levitation characteristic of this retaining structure can reduce the noise and wear generated by mechanical friction, and also makes the fan structure more compact and lightweight, which is beneficial to the miniaturization and lightweight design of the fan.

[0012] To achieve the above object, the technical solution adopted by the present invention is:

[0013] A fan stator blade retaining structure for an open rotor engine, the open rotor engine includes a splitter ring assembly, an intermediate casing, a fan stator blade and a stator blade hub. The shank of the fan stator blade is connected to the stator blade hub through a blade retaining structure, and the stator blade hub is fixed on the intermediate casing. The fan stator blade retaining structure is located between the shank and the stator blade hub and includes a magnetic levitation spherical joint. The magnetic levitation spherical joint includes an inner spherical joint shell, an outer spherical joint shell, a limiting structure and an electromagnetic force adjusting device. The inner spherical joint shell is arranged inside the outer spherical joint shell, and there is a gap between the inner spherical joint shell and the outer spherical joint shell. The end of the shank of the fan stator blade is fixedly connected to the inner spherical joint shell of the magnetic levitation spherical joint, and the outer spherical joint shell is installed in a corresponding installation cavity on the stator blade hub and then fixed on the intermediate casing. The limiting structure is arranged on the sides of the inner spherical joint shell and the outer spherical joint shell away from the shank, and is arranged along the axis of the shank between the inner spherical joint shell and the outer spherical joint shell, and there is a locally mechanically weak part on the limiting structure. The electromagnetic force adjusting device is used to control the electromagnetic force applied to the inner spherical joint shell.

[0014] Further, corresponding mounting holes are arranged along the axis of the shank on the sides of the inner spherical joint shell and the outer spherical joint shell away from the shank. Both ends of the limiting structure are installed in the mounting holes on the inner spherical joint shell and the outer spherical joint shell respectively, and the minimum cross-section of the locally mechanically weak part on the limiting structure is located in the gap part between the inner spherical joint shell and the outer spherical joint shell.

[0015] Further, the outer diameters of both ends of the limiting structure are less than or equal to the inner diameters of the mounting holes on the inner spherical joint shell and the outer spherical joint shell.

[0016] Further, the limiting structure is a pin with a necking section.

[0017] Furthermore, the locally mechanically weak part of the limiting structure is an annular groove. The cross-sectional shape of the annular groove is V-shaped, and the diameter of the locally mechanically weak part in the middle of the limiting structure is smaller than the diameters at both ends of the limiting structure. The ratio of the minimum diameter of the locally mechanically weak part to the diameters at both ends of the limiting structure is 1:3 to 1:5.

[0018] Furthermore, the electromagnetic force adjustment device is arranged on the spherical joint housing, and the electromagnetic force applied to the spherical joint inner housing is controlled through the electromagnetic force adjustment device; the electromagnetic force adjustment device is connected to the magnetic levitation control system. The magnetic levitation control system has an active control function and can adjust the current and magnetic field intensity of the electromagnetic force adjustment device in a timely manner according to the vibration and impact conditions monitored in real time, so as to control the levitation state of the magnetic levitation spherical joint.

[0019] Furthermore, an electromagnetic coil is arranged on the spherical joint housing, and the spherical joint inner housing is formed of a magnetic material. The electromagnetic force adjustment device controls the electromagnetic force applied to the spherical joint inner housing by adjusting the current of the electromagnetic coil on the spherical joint housing; alternatively, electromagnetic coils are arranged on both the spherical joint housing and the spherical joint inner housing, and the electromagnetic force adjustment device controls the electromagnetic force applied to the spherical joint inner housing by adjusting the currents of the electromagnetic coil on the spherical joint housing and the electromagnetic coil on the spherical joint inner housing.

[0020] Furthermore, the spherical joint inner housing includes a spherical body at the lower part and a connecting seat at the upper part. A connecting flange is provided at one end of the blade handle away from the fan stator blade; a plurality of connecting holes are evenly arranged on the outer circumferences 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, so as to fixedly connect the spherical joint inner housing and the blade handle.

[0021] Furthermore, the spherical body at the lower part of the spherical joint inner housing and the connecting seat at the upper part are integrally formed, and the spherical body is a hollow structure or a solid structure.

[0022] Furthermore, when the centers of the spherical joint inner housing and the spherical joint housing are aligned, the gap between the spherical joint inner housing and the spherical joint housing is 1 - 10 mm.

[0023] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in that when the fan stator blade is impacted by an external object, the impact and vibration loads transmitted to the intermediate casing can be reduced, specifically as follows:

[0024] (1) In the design of the magnetic levitation spherical joint in the present invention, the magnetic levitation technology is utilized to make the connection between the fan stator blade and the intermediate casing no longer a traditional rigid connection, but a connection with certain flexibility and buffering ability. This design allows the fan stator blade to absorb and disperse the disturbance energy through the small displacement of the spherical joint when it is slightly disturbed by the flow field, so that the fan stator blade is stably installed and operates reliably;

[0025] (2) When the load exceeds a certain threshold, the limiting structure between the inner shell and the outer shell fails at the mechanically weak part. At the same time, by adjusting the current, the electromagnetic force output by the outer shell is weakened, and the magnetic force control of the outer shell on the inner shell is reduced, so that the inner and outer surfaces of the spherical joint present a ball hinge fitting mode, reducing the load transmitted to the intermediate casing and ensuring the safety of the intermediate casing.

[0026] In addition, the magnetic levitation characteristic of the structure of the present invention enables the stator blade to rotate around the axis of the blade stalk and freely adjust its angle within a certain range, realizing the variable pitch function, and also reducing the noise and wear generated by mechanical friction. The introduction of the magnetic levitation spherical joint also makes the fan structure more compact and lightweight, which is beneficial to the miniaturization and lightweight design of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 is a schematic structural diagram of the prior art;

[0029] Figure 2 is an overall schematic diagram of the fan stator blade holding structure of the open rotor engine of the present invention;

[0030] Figure 3 is a schematic structural diagram of the magnetic levitation joint of the present invention;

[0031] Figure 4 is a schematic structural diagram of the connection structure between the blade stalk and the inner shell of the magnetic levitation spherical joint of the present invention;

[0032] Figure 5 is a schematic structural diagram of the limiting structure of the present invention.

[0033] Reference numerals in the drawings:

[0034] Shunt ring assembly 1;

[0035] Intermediate casing 2;

[0036] Fan stator blade 3;

[0037] Stator blade hub 4;

[0038] Blade stalk 5;

[0039] Connecting flange 51;

[0040] Connecting bolt 52;

[0041] Inner shell 6 of spherical joint;

[0042] Spherical body 61;

[0043] Connecting seat 62;

[0044] Outer shell 7 of spherical joint;

[0045] Limit structure 8;

[0046] Circular groove 81;

[0047] Electromagnetic force adjusting device 9;

[0048] Electromagnetic coil 91;

[0049] Magnetic levitation control system 10. Detailed implementation manners

[0050] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0052] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present invention, those skilled in the art should understand that one 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 aspects described herein can be used to implement the device and / or practice the method. In addition, this device can be implemented and this method can be practiced using other structures and / or functions in addition to one or more of the aspects described herein.

[0053] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present invention. The diagrams only show the components related to the present invention, rather than being drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0054] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the examples can be practiced without these specific details.

[0055] Meanwhile, in this specification, the description of directions, such as up, down, left, right, front, back, inside, outside, longitudinal, transverse, vertical, horizontal, etc., indicates the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0056] As Figure 2 shown, the open rotor engine of the present invention includes a splitter ring assembly 1, an intermediate case 2, fan stator vanes 3, and a stator vane hub 4. The blade shank 5 of the fan stator vane 3 is connected to the stator vane hub 4 through a blade holding structure, and the stator vane hub 4 is fixed to the intermediate case 2. In the open rotor engine, a small part of the gas flowing in from the front row of fan rotor blades enters the engine core through the splitter ring assembly 1, and most of the gas flows out after being rectified by the fan stator vanes 3 to provide thrust for the engine.

[0057] See Figure 2 and 3 , the fan stator vane holding structure of the present invention is located between the blade shank 5 of the fan stator vane and the stator vane hub 4, and includes a magnetic levitation spherical joint. The magnetic levitation spherical joint mainly includes a spherical joint inner shell 6, a spherical joint outer shell 7, a limiting structure 8, and an electromagnetic force adjusting 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 shank 5 of the fan stator vane 3 is fixedly connected to the spherical joint inner shell 6 of the magnetic levitation spherical joint, and the spherical joint outer shell 7 is installed in the corresponding installation cavity on the stator vane hub 4 and then fixed to the intermediate case 2.

[0058] The limiting structure 8 is arranged on the side of the inner spherical joint shell 6 and the outer spherical joint shell 7 away from the petiole 5, and is arranged along the axis of the petiole between the inner spherical joint shell 6 and the outer spherical joint shell 7, and there is a locally mechanically weak part on the limiting structure 8. Specifically, corresponding mounting holes are arranged along the axis of the petiole 5 on the side of the inner spherical joint shell 6 and the outer spherical joint shell 7 away from the petiole 5. The two ends of the limiting structure 8 are respectively installed in the mounting holes on the inner spherical joint shell 6 and the outer spherical joint shell 7, and the minimum cross-section of the locally mechanically weak part on the limiting structure 8 is located in the gap between the inner spherical joint shell 6 and the outer spherical joint shell 7. To ensure magnetic levitation between the inner spherical joint shell 6 and the outer spherical joint 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 inner spherical joint shell 6 and the outer spherical joint shell 7.

[0059] Preferably, the limiting structure 8 is a pin with a necking section.

[0060] The electromagnetic force adjusting device 9 is arranged on the outer spherical joint shell 7. Through the electromagnetic force adjusting device 9, the electromagnetic force applied to the inner spherical joint shell 6 can be controlled, so that the inner spherical joint shell 6 floats inside the outer spherical joint shell 7, realizing the non-contact suspension of the magnetic levitation spherical joint. The electromagnetic force adjusting device 9 is connected to the magnetic levitation control system 10. The magnetic levitation control system 10 has an active control function and can timely adjust the current and magnetic field intensity of the electromagnetic force adjusting device 9 according to the vibration and impact conditions monitored in real time, so as to control the suspension state of the magnetic levitation spherical joint.

[0061] Furthermore, an electromagnetic coil 91 is arranged on the outer spherical joint shell 7. The inner spherical joint shell 6 is formed of a magnetic material. The electromagnetic force adjusting device 9 controls the electromagnetic force applied to the inner spherical joint shell 6 by adjusting the current of the electromagnetic coil 91 on the outer spherical joint shell 7.

[0062] Or, electromagnetic coils 91 are arranged on both the outer spherical joint shell 7 and the inner spherical joint shell 6. The electromagnetic force adjusting device 9 controls the electromagnetic force applied to the inner spherical joint shell 6 by adjusting the currents of the electromagnetic coil 91 on the outer spherical joint shell 7 and the electromagnetic coil 91 on the inner spherical joint shell 6.

[0063] As Figure 3 、 4 shown, the inner spherical joint shell 6 includes a spherical body 61 at the lower part and a connecting seat 62 at the upper part. A connecting flange 51 is provided at one end of the petiole 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. Connecting bolts 52 pass through the corresponding connecting holes on the connecting seat 62 and the connecting flange 51, so as to fixedly connect the inner spherical joint shell 6 and the petiole 5 together.

[0064] Preferably, the spherical body at the lower part of the inner spherical joint shell 6 and the connecting seat at the upper part are integrally formed, and the spherical body is a hollow structure or a solid structure.

[0065] To obtain a better magnetic levitation effect, when the centers of the inner spherical joint housing 6 and the outer spherical joint housing 7 are aligned, the gap between the inner spherical joint housing 6 and the outer spherical joint housing 7 is 1 - 10 mm.

[0066] Furthermore, as Figure 5 shown, the limiting structure 8 is generally cylindrical, and a locally mechanically weak part is provided at the middle position. The specific form of the locally mechanically 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 locally mechanically 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 locally mechanically weak part to the diameters at both ends of the limiting structure 8 is 1:3 - 1:5.

[0067] Since the end of the petiole 5 of the fan stator blade 3 is fixedly connected to the inner spherical joint housing 6 of the magnetic levitation spherical joint, the inner spherical joint housing 6 bears the self-load of the fan stator blade 3, the aerodynamic load on the fan stator blade 3, and the pitch drive load of the fan stator blade 3. In the present invention, the pitch drive load of the fan stator blade 3 is the electromagnetic force generated by the magnetic levitation spherical joint.

[0068] When the open rotor engine is operating normally, due to the constraint of the limiting structure 8 between the inner spherical joint housing 6 and the outer spherical joint housing 7, the fan stator blade 3 can rotate around the axis of the petiole 5 under the drive of the electromagnetic force controlled by the electromagnetic force adjustment device of the outer spherical joint housing 7, so as to realize the function of adjusting the pitch angle of the fan stator blade 3 and ensure the normal operation of the open rotor engine. At this time, the magnetic levitation spherical joint makes the connection between the fan stator blade 3 and the stator blade hub 4 no longer a traditional rigid connection, but has a certain flexibility and buffering ability, which helps the stable operation of the fan stator blade 3.

[0069] When the impact load transmitted from the fan stator vane 3 through the blade shank 5 and the inner shell 6 of the spherical joint to the outer shell 7 of the spherical joint exceeds the set threshold of the limit structure 8, the limit structure 8 between the inner shell 6 and the outer shell 7 of the spherical joint will fail at the mechanically weak part and break. At this time, due to the structural characteristics of the inner shell 6 and the outer shell 7 of the magnetic levitation spherical joint, the outer shell 7 of the spherical joint can still provide sufficient restraint for the inner shell 6 of the spherical joint, thereby ensuring that the blade shank 5 will not fly out, enabling the fan stator vane 3 to maintain sufficient structural integrity and ensuring 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, weakens the output electromagnetic force, reduces the electromagnetic force control on the inner shell 6 of the spherical joint, so that the inner and outer surfaces of the spherical joint still present a magnetic levitation ball joint matching mode, and the fan stator vane can rotate arbitrarily in three directions. Due to the fracture failure of the limit structure 8 and the reduction of the electromagnetic force applied to the inner shell 6 of the spherical joint, it is very difficult for the impact load of the fan stator vane 3 to be transmitted from the inner shell 6 of the spherical joint to the outer shell 7 of the spherical joint, thereby avoiding the intermediate casing 2 from being affected by the impact load.

[0070] Through the failure and fracture of the limit structure 8 in the stator vane retention structure, on the one hand, the rotational restraint of the fan stator vane 3 at the blade root can be released, enabling the fan stator vane 3 to swing with the airflow excitation, thereby converting most of the energy received by the fan stator vane 3 into the kinetic energy of the fan stator vane 3 and reducing the internal energy generated by the fan stator vane 3 and transmitted outward; on the other hand, the failure and fracture of the limit structure 8 and the weak coupling between the inner shell 6 and the outer shell 7 of the spherical joint can weaken the impact and vibration load transmission path between the fan stator vane 3 and the intermediate casing 2, fully ensuring the safety of the intermediate casing.

[0071] As described above, it is only the specific implementation manner 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 those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should 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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