A turbofan engine coupling device

Abstract

The application discloses a turbofan engine coupling device, which comprises a coupling structure connected between a fan of a turbofan engine and a rotor of the turbofan engine; the coupling structure comprises a rotor shaft, a fan shaft structure and a floatable coupling piece; one end of the rotor shaft is connected with the rotor of the turbofan engine; the fan shaft structure is sleeved on the outer surface of the rotor shaft at one end close to the rotor shaft, and the other end of the fan shaft structure is adapted to be connected with the fan of the turbofan engine; the floatable coupling piece is installed at the connecting position of the rotor shaft and the fan shaft structure, and the floatable coupling piece comprises rollers and first and second shaft rings oppositely arranged on both sides of the rollers; the first shaft ring is connected with the rotor shaft, and the second shaft ring is connected with the fan shaft structure. The structure can make the axial force of the turbine and the axial force of the fan shaft structure and the rotor shaft counteract each other, can reduce the axial load borne by the rotor shaft and the fan shaft structure, and is favorable for the reliability and service life of the engine shaft system.

Description

Technical Field

[0001] This invention relates to the technical field of military and civilian aviation, specifically to a turbofan engine coupling device. Background Technology

[0002] The GTF engine, academically known as a geared turbofan engine, differs from traditional engines in that its fan is connected to the low-pressure rotor via a planetary gearbox. This allows the low-pressure compressor to operate at higher speeds, while the fan operates at lower speeds with lower aerodynamic losses and noise. This, combined with an increased bypass ratio, results in lower fuel consumption and noise levels. Consequently, an increasing number of civil aviation engines are now using GTF engines.

[0003] Traditional twin-shaft direct-drive engines utilize the interaction between the fan, low-pressure compressor, and low-pressure turbine to offset most of the rotor axial force, reducing the axial load on the rotor support bearings and thus improving bearing reliability and lifespan. However, the GTF engine introduces a planetary gearbox, which only transmits torque and not axial force. This eliminates the axial force offsetting mechanism between the rotor shafts, forcing the GTF engine to withstand the enormous fan and low-pressure rotor axial forces individually through its own rotor support bearings. This results in massive bearing dimensions and complex force transmission structures, directly impacting the GTF's efficiency and lifespan. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this invention is that the huge axial force of the fan and the axial force of the low-pressure rotor of the GTF engine cannot cancel each other out, and each rotor support bearing needs to withstand them separately. This results in huge bearing structure size and complex support force transmission structure, which directly affects the efficiency and service life of the GTF.

[0005] Therefore, the present invention provides a turbofan engine coupling device, comprising:

[0006] A coupling structure connecting the turbofan engine fan and the turbofan engine rotor; the coupling structure includes:

[0007] A rotor shaft, one end of which is connected to the turbofan engine rotor;

[0008] A fan shaft structure, wherein the fan shaft structure is annular, one end of the fan shaft structure near the rotor shaft is sleeved on the outer surface of the rotor shaft, and the other end of the fan shaft structure is adapted to be connected to the turbofan engine fan;

[0009] And a floating coupling, which is installed at the connection position between the rotor shaft and the fan shaft structure. The floating coupling includes a roller and a first shaft ring and a second shaft ring disposed opposite to each other on both sides of the roller. The first shaft ring and the second shaft ring are connected and can rotate relative to each other. The first shaft ring is connected to the rotor shaft and the second shaft ring is connected to the fan shaft structure.

[0010] Optionally, the above-mentioned floating coupling also includes rollers, with the first shaft ring and the second shaft ring disposed opposite each other on both sides of the rollers;

[0011] Wherein, the inner diameter of the second shaft ring is larger than the inner diameter of the first shaft ring, and the outer diameter of the second shaft ring is larger than the outer diameter of the first shaft ring;

[0012] When the floating coupling is positioned at the connection point between the rotor shaft and the fan shaft structure; the inner wall of the first shaft ring is connected to the outer wall of the rotor shaft, and the first shaft ring and the fan shaft structure are spaced apart to form a first ring gap; the outer wall of the second shaft ring is connected to the inner wall of the fan shaft structure, and the second shaft ring and the rotor shaft are spaced apart.

[0013] Optionally, the above-mentioned fan shaft structure includes: a fan shaft body and a mounting portion, both of which are annular, the mounting portion being disposed at one end of the fan shaft body near the rotor shaft, and the mounting portion being spaced apart from the rotor shaft to form a second annular gap.

[0014] Optionally, the mounting portion near one side of the turbofan engine fan, the inner wall of the fan shaft body, and the outer wall of the rotor shaft form a mounting area, and the floating coupling is adapted to be installed in the mounting area.

[0015] Optionally, the above-mentioned fan shaft structure further includes: a first oil inlet hole, the first oil inlet hole being formed on the fan shaft body, the oil inlet end of the first oil inlet hole being connected to the outer side of the fan shaft body, and the oil outlet end of the first oil inlet hole being adapted to face the first annular gap to introduce oil into the first annular gap to form an annular oil film.

[0016] Optionally, the rotor shaft is further provided with a second oil inlet hole, the oil inlet end of the second oil inlet hole being located on the side of the rotor shaft away from the fan shaft structure; the oil outlet end of the second oil inlet hole is directed toward the second annular gap to introduce oil into the second annular gap to form an annular oil film.

[0017] Optionally, the aforementioned second oil inlet hole is opened along the radial direction of the rotor shaft;

[0018] The second oil inlet hole is provided in a plurality of such holes, and the second oil inlet holes are evenly spaced along the circumferential direction of the rotor shaft.

[0019] Optionally, the rotor shaft is provided with an oil slinger hole, the oil inlet end of which is located on the side of the rotor shaft away from the fan shaft structure; the oil outlet end of which is located towards the roller.

[0020] Optionally, the above-mentioned fan shaft structure further includes: an oil drain hole, the oil drain hole being formed on the fan shaft body, the oil inlet end of the oil drain hole being adapted to face the mounting area, and the oil outlet end of the oil drain hole being adapted to be disposed facing the outside of the fan shaft body to drain the oil in the mounting area.

[0021] Optionally, the aforementioned turbofan engine coupling device further includes a gear transmission structure, which includes gears evenly distributed circumferentially along the rotor shaft. The outer end of the gear transmission structure is connected to the fan shaft structure, and the inner end of the gear transmission structure is adapted to be connected to the rotor shaft.

[0022] The technical solution provided by this invention has the following advantages:

[0023] 1. The turbofan engine coupling device provided by the present invention includes a coupling structure connecting the turbofan engine fan and the turbofan engine rotor; the coupling structure includes: a rotor shaft, a fan shaft structure, and a floating coupling member; one end of the rotor shaft is connected to the turbofan engine rotor; the fan shaft structure is annular, with one end of the fan shaft structure near the rotor shaft sleeved on the outer surface of the rotor shaft, and the other end of the fan shaft structure adapted to be connected to the turbofan engine fan; the floating coupling member is installed at the connection position between the rotor shaft and the fan shaft structure, and the floating coupling member includes a first shaft ring and a second shaft ring arranged opposite to each other, the first shaft ring and the second shaft ring being rotatable relative to each other; the first shaft ring is connected to the rotor shaft, and the second shaft ring is connected to the fan shaft structure.

[0024] On the one hand, this design ensures that the rotation between the rotor shaft and the fan shaft structure remains unaffected, guaranteeing normal bearing operation. On the other hand, compared to existing GTF engines, this application, by installing a floating coupling at the connection point between the rotor shaft and the fan shaft structure, connects to both the rotor shaft and the fan shaft structure. While maintaining decoupling of the fan shaft structure and rotor shaft speeds, the axial force between the fan shaft structure and the rotor shaft is forward, while the axial force of the turbine is backward, with opposite directions of action. Therefore, by connecting the fan shaft structure and the rotor shaft with the floating coupling, the axial force of the turbine and the axial force between the fan shaft structure and the rotor shaft can cancel each other out, similar to a tug-of-war. This reduces the axial load on the rotor shaft and fan shaft structure, reducing the difficulty of supporting the fan and low-pressure rotor front end while maintaining the original performance and efficiency of the GTF turbofan engine, thus benefiting the reliability and lifespan of the engine shaft system.

[0025] 2. The turbofan engine coupling device provided by this invention utilizes a gear transmission structure and a floating coupling to transmit torque and axial force respectively. The axial forces generated by the fan and the main engine can cancel each other out, eliminating the need for independent balancing. Therefore, the load-bearing capacity of the engine's support casing is reduced compared to existing turbofan engines, lowering the design requirements of the casing. The floating coupling can transfer the axial load of the rotor shaft to the fan shaft structure, allowing for a smaller size at the rotor shaft's front end support. Compared to existing technologies, it eliminates the need for multiple sets of thrust bearings for support and load-bearing, thus avoiding unnecessary space occupation within the GTF turbofan engine and not affecting the design of other structures within the GTF turbofan engine, thereby ensuring the overall performance of the turbofan engine.

[0026] 3. The first shaft ring and the fan shaft structure provided by the present invention are spaced apart to form a first annular gap; and the mounting part and the rotor shaft are spaced apart to form a second annular gap; the fan shaft structure further includes: a first oil inlet hole, which is opened on the fan shaft body, the first oil inlet hole is opened at an angle, the oil inlet end of the first oil inlet hole is connected to the outer side of the fan shaft body, the oil outlet end of the first oil inlet hole is adapted to be set towards the first annular gap, and the opening direction of the first oil inlet hole is opposite to the working rotation direction of the fan shaft. During the rotation, the first oil inlet hole can draw lubricating oil from the outer surface to the first annular gap to form an annular oil film; a second oil inlet hole is also opened on the rotor shaft. The oil inlet end of the second oil inlet is located on the side of the rotor shaft away from the fan shaft structure; the oil outlet end of the second oil inlet faces the second annular gap, and the second oil inlet is opened along the radial direction of the rotor shaft; during the rotation of the rotor shaft, the centrifugal force of the rotation throws the lubricating oil in the rotor shaft core into the second annular gap between the floating coupling and the rotor shaft to form an annular oil film. Through the above arrangement, an oil film is formed in the first annular gap and the second annular gap, which can ensure the concentricity of the fan shaft structure and the rotor shaft, and the fluidity of the oil film can consume the vibration energy of the fan shaft structure and the rotor shaft to avoid excessive vibration and play a vibration reduction role. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the turbofan engine in this invention;

[0029] Figure 2 This is a schematic diagram of the turbofan engine coupling device in this invention;

[0030] Figure 3 For the present invention Figure 2 A magnified view of part A in the diagram;

[0031] Explanation of reference numerals in the attached figures:

[0032] 1 - Turbofan engine fan;

[0033] 2 - Turbofan engine rotor;

[0034] 3- Gear transmission structure;

[0035] 4 – Coupling structure; 41 – Rotor shaft; 411 – Second oil inlet; 412 – Oil slinger hole; 42 – Fan shaft structure; 421 – Fan shaft body; 422 – Mounting part; 423 – First oil inlet; 424 – Oil drain hole; 43 – Floating coupling; 431 – First shaft ring; 432 – Roller; 433 – Second shaft ring; 44 – First ring clearance; 45 – Second ring clearance. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Example 1

[0041] This embodiment provides a coupling device for a turbofan engine, such as... Figures 1 to 3 As shown, the turbofan engine includes: a casing and a turbofan engine fan 1 and a turbofan engine rotor 2 disposed inside the casing. The turbofan engine coupling device includes a coupling structure 4, which is disposed between the turbofan engine fan 1 and the turbofan engine rotor 2, and both ends of the coupling structure 4 are respectively connected to the turbofan engine fan 1 and the turbofan engine rotor 2.

[0042] The coupling structure 4 includes a rotor shaft 41, a fan shaft structure 42, a floating coupling 43, and a gear transmission structure 3. The turbofan engine coupling device also includes the gear transmission structure 3, which includes gears evenly distributed along the circumference of the rotor shaft 41. The outer end of the gear transmission structure 3 is connected to the fan shaft structure 42, and the inner end of the gear transmission structure 3 is adapted to connect to the rotor shaft 41. The fan shaft structure 42 is an overall annular cylindrical structure with a "J"-shaped longitudinal section of its annular wall. One end of the fan shaft structure 42 is connected to the turbofan engine fan 1, and the other end of the fan shaft structure 42 is sleeved on the outer wall of the rotating shaft. The end of the rotor shaft 41 away from the fan shaft structure 42 is connected to the turbofan engine rotor 2. The floating coupling 43 is a thrust bearing, and the floating coupling 43 is secured by a bearing and a clamping nut. The floating coupling 43, located at the connection point between the rotor shaft 41 and the fan shaft structure 42, includes a first shaft ring 431, rollers 432, and a second shaft ring 433. Alternatively, a bearing clamping nut can be used to press the first shaft ring 431, rollers 432, and second shaft ring 433 into the mounting area, forming a stable bearing fit. Several rollers 432 are provided, and the first shaft ring 431 and second shaft ring 433 are positioned opposite each other on both sides of the rollers 432. Under the action of the rotor, the first shaft ring 431 and second shaft ring 433 can rotate around their center position. The first shaft ring 431 is connected to the rotor shaft 41, and the second shaft ring 433 is connected to the fan shaft structure 42. This ensures that the rotation between the rotor shaft 41 and the fan shaft structure 42 is unaffected, guaranteeing normal bearing operation.

[0043] On the other hand, compared with the existing GTF engine, this application installs a floating coupling 43 at the connection position of the rotor shaft 41 and the fan shaft structure 42, and the floating coupling 43 is connected to the rotor shaft 41 and the fan shaft structure 42 respectively. While keeping the rotational speeds of the fan shaft structure 42 and the rotor shaft 41 decoupled, the axial force of the fan shaft structure 42 and the rotor shaft 41 is forward, and the axial force of the turbine is backward. The two forces act in opposite directions and can cancel each other out. Therefore, by connecting the fan shaft structure 42 and the rotor shaft 41 through the floating coupling 43, the axial force of the turbine and the axial force of the fan shaft structure 42 and the rotor shaft 41 can cancel each other out, similar to the force dissipation method of "tug-of-war". This can reduce the axial load on the rotor shaft 41 and the fan shaft structure 42. While ensuring the original performance and efficiency of the GTF turbofan engine, it reduces the difficulty of supporting the fan and the front end of the low-pressure rotor, which is beneficial to the reliability and life of the engine shaft system.

[0044] Furthermore, by utilizing the gear transmission structure 3 and the floating coupling 43 to transmit torque and axial force respectively, the axial forces generated by the fan and the main engine can cancel each other out, eliminating the need for independent balancing. Therefore, the load-bearing capacity of the engine support casing is reduced compared to existing turbofan engines, thus lowering the design requirements of the casing.

[0045] The floating coupling 43 can transfer the axial load of the rotor shaft 41 to the fan shaft structure 42, so the front end support of the rotor shaft 41 can be of a small size. Compared with the prior art, it is not necessary to use multiple sets of thrust bearings to achieve the purpose of support and load bearing, thus it will not occupy extra space in the GTF turbofan engine, nor will it affect the design of other structures in the GTF turbofan engine, ensuring the performance of the entire turbofan engine.

[0046] Among them, the floating coupling 43 can be a single-row thrust cylindrical roller bearing. If the axial load is too large, a multi-row thrust cylindrical roller bearing can be selected. If it is necessary to bear part of the radial force, a thrust tapered roller 432 bearing or a thrust self-aligning roller 432 bearing can be selected.

[0047] Specifically, such as Figure 2 and Figure 3 As shown, the fan shaft structure 42 includes a fan shaft body 421 and a mounting portion 422. Both the fan shaft body 421 and the mounting portion 422 are annular. The mounting portion 422 is located at one end of the fan shaft body 421 near the rotor shaft 41, and is positioned between the fan shaft body 421 and the rotor shaft 41. The fan shaft body 421 and the mounting portion 422 are integrally formed, and the longitudinal cross-section of their annular walls is J-shaped. Figure 3As shown, the mounting part 422, near the side of the turbofan engine fan 1 (i.e., the left side of the mounting part 422), and the inner wall of the fan shaft body 421 and the outer wall of the rotor shaft 41 form an annular mounting area. A floating coupling 43 is fitted onto the outer wall of the rotor shaft 41 via a bearing clamping nut and is installed within the mounting area. Regarding the floating coupling 43, the first shaft ring 431 and the second shaft ring 433 on the floating coupling 43 are concentrically arranged. The inner diameter of the second shaft ring 433 is larger than the inner diameter of the first shaft ring 431. The outer diameter of the second shaft ring 433... The diameter of the second shaft ring 433 is larger than the outer diameter of the first shaft ring 431. When the floating coupling 43 is installed in the annular mounting area, the inner wall of the first shaft ring 431 is tightly fitted to the outer wall of the rotor shaft 41, while the outer wall of the second shaft ring 433 is interference-fitted onto the inner wall of the fan shaft body 421 and the left inner wall of the mounting part 422. The second shaft ring 433 is tightly fitted to the left inner wall of the mounting part 422. Furthermore, the outer wall of the first shaft ring 431 does not contact the inner wall of the fan shaft body 421, and the inner wall of the second shaft ring 433 does not contact the inner wall of the rotor shaft 41 and maintains a large gap. Since the rotational speeds of the fan shaft structure 42 and the rotor shaft 41 are inconsistent, the above arrangement ensures that when the floating coupling 43 is installed in the mounting area, the fan shaft structure 42 and the rotor shaft 41 will not interfere with each other, ensuring the normal operation of the entire device.

[0048] In this embodiment, as Figure 2 and Figure 3As shown, the first shaft ring 431 and the fan shaft structure 42 are spaced apart to form a first annular gap 44; and the mounting part 422 and the rotor shaft 41 are spaced apart to form a second annular gap 45; the fan shaft structure 42 also includes: a first oil inlet 423, which is opened on the fan shaft body 421. The first oil inlet 423 is opened at an angle, and the oil inlet end of the first oil inlet 423 is connected to the outer side of the fan shaft body 421. The oil outlet end of the first oil inlet 423 is adapted to be set towards the first annular gap 44. The opening direction of the first oil inlet 423 is opposite to the working rotation direction of the fan shaft. During rotation, the first oil inlet 423 can draw lubricating oil from the outer surface to the first annular gap 44 to form an annular oil film; a second oil inlet 411 is also opened on the rotor shaft 41. The oil inlet end of the oil hole 411 is located on the side of the rotor shaft 41 away from the fan shaft structure 42; the oil outlet end of the second oil inlet 411 faces the second annular gap 45, and the second oil inlet 411 is opened along the radial direction of the rotor shaft 41. The second oil inlet 411 is a radial through hole. During the rotation of the rotor shaft 41, the centrifugal force of the rotation throws the lubricating oil in the shaft of the rotor shaft 41 into the second annular gap 45 between the floating coupling 43 and the rotor shaft 41 to form an annular oil film. Through the above arrangement, an oil film is formed in the first annular gap 44 and the second annular gap 45, which can ensure the concentricity of the fan shaft structure 42 and the rotor shaft 41. Moreover, the fluidity of the oil film can consume the vibration energy of the fan shaft structure 42 and the rotor shaft 41 to avoid excessive vibration and play a vibration reduction role.

[0049] Among them, such as Figure 2 and Figure 3 As shown, there are several first oil inlets 423 and several second oil inlets 411. Several first oil inlets 423 are spaced apart along the circumferential direction of the fan shaft body 421, and several second oil inlets 411 are spaced apart along the circumferential direction of the rotor shaft 41. This ensures that while the fan shaft structure 42 and the rotor shaft 41 are rotating, oil can be quickly introduced and filled into all positions in the first ring gap 44 and the second ring gap 45, thus ensuring the vibration reduction effect on the fan shaft structure 42 and the rotor shaft 41.

[0050] In this embodiment, as Figure 2 and Figure 3As shown, an oil-throwing hole 412 is provided on the rotor shaft 41. The oil inlet end of the oil-throwing hole 412 is located on the side of the rotor shaft 41 away from the fan shaft structure 42; the oil outlet end of the oil-throwing hole 412 is located facing the roller 432; the oil-throwing hole 412 is a radial through hole, which uses the centrifugal force of rotation to throw the lubricating oil in the shaft into the gap between the first shaft ring 431 and the second shaft ring 433 of the floating coupling 43, so as to lubricate and cool the floating coupling 43; the fan shaft structure 42 also includes an oil drain hole 424. The oil drain hole 424, which is located on the fan shaft body 421, has its oil inlet end facing the installation area and its oil outlet end facing the outside of the fan shaft body 421. Specifically, the oil inlet end of the oil drain hole 424 is facing the gap between the first shaft ring 431 and the second shaft ring 433. It is composed of a radial through blind hole and an axial blind hole. It uses the centrifugal force of rotation to discharge the lubricating oil that has been lubricated and cooled by the floating coupling 43, and promptly removes impurities and heat to ensure the operating environment of the floating coupling 43.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A coupling device for a turbofan engine, characterized in that, include: A coupling structure (4) connecting the turbofan engine fan (1) and the turbofan engine rotor (2); The coupling structure (4) includes: Rotor shaft (41), one end of which is connected to the turbofan engine rotor (2); A fan shaft structure (42) is annular. One end of the fan shaft structure (42) near the rotor shaft (41) is sleeved on the outer surface of the rotor shaft (41), and the other end of the fan shaft structure (42) is adapted to be connected to the turbofan engine fan (1). And a floating coupling (43) is installed at the connection position between the rotor shaft (41) and the fan shaft structure (42). The floating coupling (43) includes a roller and a first shaft ring (431) and a second shaft ring (433) disposed opposite to each other on both sides of the roller. The first shaft ring (431) and the second shaft ring (433) are connected and can rotate relative to each other. The first shaft ring (431) is connected to the rotor shaft (41), and the second shaft ring (433) is connected to the fan shaft structure (42).

2. The turbofan engine coupling device according to claim 1, characterized in that, The inner diameter of the second shaft ring (433) is larger than the inner diameter of the first shaft ring (431), and the outer diameter of the second shaft ring (433) is larger than the outer diameter of the first shaft ring (431). When the floating coupling (43) is positioned at the connection point between the rotor shaft (41) and the fan shaft structure (42), the inner wall of the first shaft ring (431) is connected to the outer wall of the rotor shaft (41), and the first shaft ring (431) and the fan shaft structure (42) are spaced apart to form a first annular gap (44); the outer wall of the second shaft ring (433) is connected to the inner wall of the fan shaft structure (42), and the second shaft ring (433) and the rotor shaft (41) are spaced apart.

3. The turbofan engine coupling device according to claim 2, characterized in that, The fan shaft structure (42) includes a fan shaft body (421) and a mounting part (422). Both the fan shaft body (421) and the mounting part (422) are annular. The mounting part (422) is disposed at one end of the fan shaft body (421) near the rotor shaft (41), and the mounting part (422) and the rotor shaft (41) are spaced apart to form a second annular gap (45).

4. The turbofan engine coupling device according to claim 3, characterized in that, The mounting part (422) is located near one side of the turbofan engine fan (1), the inner wall of the fan shaft body (421) and the outer wall of the rotor shaft (41) to form a mounting area, and the floating coupling (43) is adapted to be installed in the mounting area.

5. The turbofan engine coupling device according to claim 4, characterized in that, The fan shaft structure (42) further includes: a first oil inlet hole (423), which is opened on the fan shaft body (421). The oil inlet end of the first oil inlet hole (423) is connected to the outside of the fan shaft body (421), and the oil outlet end of the first oil inlet hole (423) is adapted to face the first annular gap (44) to introduce oil into the first annular gap (44) to form an annular oil film.

6. The turbofan engine coupling device according to claim 4, characterized in that, The rotor shaft (41) is also provided with a second oil inlet hole (411), the oil inlet end of the second oil inlet hole (411) is located on the side of the rotor shaft (41) away from the fan shaft structure (42); the oil outlet end of the second oil inlet hole (411) is directed toward the second annular gap (45) to introduce oil into the second annular gap (45) to form an annular oil film.

7. The turbofan engine coupling device according to claim 6, characterized in that, The second oil inlet (411) is opened along the radial direction of the rotor shaft (41); The second oil inlet hole (411) is provided in a plurality of such holes, and the second oil inlet hole (411) is evenly spaced along the circumferential direction of the rotor shaft (41).

8. The turbofan engine coupling device according to claim 7, characterized in that, The rotor shaft (41) is provided with an oil-throwing hole (412), the oil inlet end of the oil-throwing hole (412) is located on the side of the rotor shaft (41) away from the fan shaft structure (42); the oil outlet end of the oil-throwing hole (412) is located towards the roller (432).

9. The turbofan engine coupling device according to claim 4, characterized in that, The fan shaft structure (42) further includes an oil drain hole (424), which is formed on the fan shaft body (421). The oil inlet end of the oil drain hole (424) is adapted to face the mounting area, and the oil outlet end of the oil drain hole (424) is adapted to face the outside of the fan shaft body (421) to drain the oil in the mounting area.

10. The turbofan engine coupling device according to any one of claims 1-9, characterized in that, The turbofan engine coupling device further includes a gear transmission structure (3), which includes gears evenly distributed circumferentially along the rotor shaft (41). The outer end of the gear transmission structure (3) is connected to the fan shaft structure (42), and the inner end of the gear transmission structure (3) is adapted to be connected to the rotor shaft (41).

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