Main drive shaft assembly for coaxial dual rotor tip jet system and method of manufacture

Abstract

The application relates to a main transmission shaft assembly for a coaxial double-rotor blade-tip jet system and a manufacturing method, and belongs to the technical field of coaxial double-rotor blade-tip jet transmission shafts. The main transmission shaft assembly solves the problems that the transmission shaft in the prior art is difficult to meet the long-term strength under high-temperature working conditions and the reliability of the connection with the rotor is low. The main transmission shaft assembly comprises a shaft body extending longitudinally and having a hollow internal passage, a connecting disc spline located at the upper end of the shaft body, and a main shaft driven gear connecting flange located at the lower end of the shaft body. An upper rotor connecting device is arranged at the upper end of the main transmission shaft and is connected with the connecting disc spline, and is used for connecting the main transmission shaft with the upper rotor. A main transmission shaft locking device is arranged at the upper end port of the main transmission shaft and is located on the upper side of the upper rotor connecting device, and is used for locking the upper rotor connecting device to the main transmission shaft. A main shaft driven gear assembly is arranged at the lower end of the main transmission shaft and is connected with the main shaft driven gear connecting flange, and is used for receiving driving force from a power system.

Description

Technical Field

[0001] This invention relates to the field of coaxial dual rotor tip jet drive shaft technology, and more specifically to a main drive shaft assembly and manufacturing method for a coaxial dual rotor tip jet system. Background Technology

[0002] In a coaxial twin-rotor tip-jet propulsion system, the main drive shaft assembly is crucial. It needs to support and drive one of the rotors, maintain high-speed rotation during operation, and withstand significant mechanical loads. Considering the space required for the transmission mechanisms of the upper and lower rotors, the main drive shaft has a long longitudinal dimension, making it a long shaft. Because it transports the gas generated by the gas turbine to the rotor tips to generate thrust, high-temperature, high-pressure gas passes through the outside of the main drive shaft, resulting in a high-temperature operating environment. Therefore, it needs high static strength and high-temperature creep strength. Simultaneously, the high-temperature, high-pressure gas is highly corrosive, requiring the main drive shaft to have good corrosion resistance. Furthermore, to ensure the spacing between the upper and lower rotors for a reasonable aerodynamic structure, the main drive shaft should also have good dimensional stability. Finally, as a connecting component to the rotors, the reliability of the connection must be considered. During rotor assembly, the main drive shaft is also a vital component, ensuring a constant phase difference between the upper and lower rotors and possessing several important assembly dimensions and positioning slots. Therefore, the main drive shaft needs to have good mechanical and machinability properties.

[0003] In summary, the main difficulties and problems in the manufacturing and application of the main drive shaft are as follows: 1) The main drive shaft connects the power system to the upper rotor, and space needs to be left for the installation and operation of the lower rotor in its extension direction, making it difficult to ensure high coaxiality and transmission accuracy; 2) The main drive shaft has high strength requirements, requiring high overall strength and mechanical properties; 3) Since the outside of the main drive shaft needs to be exposed to high-temperature corrosive gas, it is prone to corrosion and deformation damage; 4) The end of the main drive shaft is connected to the rotor drive, and the rotor is prone to loosening under high speed and high torque working conditions, making it difficult to maintain a reliable connection.

[0004] Chinese utility model patent, publication number CN 203463563 U, entitled "Transmission Mechanism for Twin-Rotor Helicopters," includes a main drive shaft that drives the upper rotor to rotate, and a main drive shaft that drives the sun gear to rotate, thereby driving the lower rotor to rotate. However, the main drive shaft in this design is a solid structure, and the drive for the upper and lower rotors is provided solely through shaft rotation, which cannot meet the transmission requirements of a tip-jet twin-rotor system.

[0005] Existing main drive shafts are all solid shafts with large deflection. There is a need in this technical field for an improved main drive shaft for coaxial twin-rotor tip jet aircraft. Summary of the Invention

[0006] In view of the above problems, the present invention provides a main drive shaft assembly and manufacturing method for a coaxial twin-rotor tip jet system, which can realize the functions of supporting and transmitting power to the rotor; it also has high coaxiality, and deep internal drilling allows for cooling air to dissipate heat from the main drive shaft, improving its high-temperature strength; it has an end-locking anti-loosening function to ensure the reliability of the upper rotor and the main drive shaft. The main drive shaft in the main drive shaft assembly for a coaxial twin-rotor tip jet system provided by the present invention is a hollow shaft, which is difficult to process. The machining damping of a long hollow shaft is smaller, and attention should be paid to vibration during machining, but it is lighter in weight. While ensuring the mechanical performance and thermal stability of the drive shaft, it helps to reduce the weight of the transmission structure and improve transmission efficiency.

[0007] According to one embodiment of the present invention, a main drive shaft assembly for a coaxial twin-rotor tip jet system is provided for connecting the upper rotor of a coaxial twin-rotor tip jet aircraft to the fuselage, providing support and drive functions for the upper rotor, including: The main drive shaft includes a longitudinally extending shaft body with a hollow internal channel, a connecting disc spline located at the upper end of the shaft body, and a main shaft driven gear connecting flange located at the lower end of the shaft body, wherein the hollow internal channel of the main drive shaft body serves as a cooling air channel; The upper rotor connecting device is located at the upper end of the main drive shaft and is splinedly connected to the connecting disc, and is used to connect the main drive shaft and the upper rotor. The main drive shaft locking device is located at the upper end of the main drive shaft and above the upper rotor connecting device, and is used to lock the upper rotor connecting device to the main drive shaft. The driven gear assembly of the main shaft is located at the lower end of the main drive shaft and is connected to the driven gear connecting flange of the main shaft, and is used to receive driving force from the power system; The main drive shaft, the upper rotor connecting device, and the main shaft driven gear assembly are coaxially arranged.

[0008] Optionally, the length of the main drive shaft ranges from 1.4 to 1.6 m, the outer diameter ranges from 45 to 50 mm, and the inner diameter ranges from 35 to 40 mm.

[0009] Optionally, the internal hollow channel of the main drive shaft body is composed of a large-diameter flow channel inside the main drive shaft and a small-diameter flow channel at the end of the main drive shaft; Specifically, the position of the small-diameter flow channel at the end of the main drive shaft corresponds to the position of the spline on the connecting disc; the small-diameter flow channel at the end of the main drive shaft is located above the large-diameter flow channel at the end of the main drive shaft and they are connected to each other; the radial diameter of the small-diameter flow channel at the end of the main drive shaft is smaller than the radial diameter of the large-diameter flow channel at the end of the main drive shaft.

[0010] Optionally, the main drive shaft also includes: an upper positioning part and a lower positioning part of the main drive shaft sealing assembly, located at the lower end of the shaft body, and respectively above and below the main shaft driven gear connecting flange, for use in installing the brush seal structure.

[0011] Optionally, the upper rotor connecting device includes: The upper rotor connecting plate is splinedly connected to the connecting plate of the main drive shaft; The connecting disc sealing plate is fixed on the upper side of the upper rotor connecting disc; Multiple upper rotor connecting screws are located on the connecting disc sealing plate and are used to tighten them to the mounting part of the upper rotor.

[0012] Optionally, the outer diameter of the upper rotor connecting plate is in the range of 230-250mm; the outer diameter of the connecting plate sealing plate is the same as that of the upper rotor connecting plate; the upper rotor connecting screws are arranged on the connecting plate sealing plate in a coaxial ring layout of 2-4 turns from the inside to the outside.

[0013] Optionally, the main drive shaft locking device includes: a main drive shaft locking upper nut and a main drive shaft locking lower nut, which are rotated and locked in the same direction to the upper end port of the shaft body, and clamp and fix the upper rotor connecting disc of the lower upper rotor connecting device to the main drive shaft.

[0014] According to another embodiment of the present invention, a method for manufacturing a main drive shaft assembly for a coaxial twin-rotor tip jet system is provided, comprising: S1: Machining and preparing the main drive shaft, including making a long mandrel using alloy structural steel; machining a flange connection weld on the mandrel, welding the main shaft driven gear connection flange, drilling to form the large-diameter flow channel inside the main drive shaft and the small-diameter flow channel at the end of the main drive shaft, turning to form the shaft body of the main drive shaft, machining the main shaft driven gear screw connection positioning part, and milling the spline of the connection disc; S2: Assemble the prepared main drive shaft with the pre-prepared main drive shaft locking device, upper rotor connecting device, and main shaft driven gear assembly to obtain the main drive shaft assembly for the coaxial twin rotor tip jet system.

[0015] Optionally, S1 includes: S1.1: Using 35CrMo as the shaft material for the main drive shaft, a long mandrel is made; S1.2: Use a CNC lathe to machine a flange connection weld at the bottom of the mandrel; S1.3: Weld the pre-prepared spindle driven gear connecting flange to the lower end of the mandrel using argon arc welding; S1.4: Heat treat the processed mandrel; S1.5: Deeply drill holes in the heat-treated mandrel to machine the large-diameter flow channel inside the main drive shaft, and perform a variable-diameter opening process at the upper end of the mandrel to machine the small-diameter flow channel at the end of the main drive shaft to form an internal cooling gas channel. S1.6: Use a CNC lathe to machine the outside of the mandrel after deep drilling to obtain the shaft body. The outer diameter of the machined shaft body shall not exceed 50mm. S1.7: Use a horizontal machining center to mill the spindle driven gear screw connection positioning part on the driven gear connecting flange; S1.8: Use a four-axis machining center to mill the spline of the connecting disc on the upper end of the shaft to obtain the main drive shaft; S1.9: The main drive shaft is machined to remove burrs, blunt sharp edges, and smooth the sharp edges of the surface.

[0016] Optionally, S2 includes: S2.1: The driven gear of the main shaft and the driven gear connecting flange of the main shaft driven gear assembly are welded together; S2.2: Assemble the upper rotor connecting plate of the upper rotor connecting device with the connecting plate spline at the upper end of the main drive shaft, and lock the upper rotor connecting plate to the main drive shaft through the main drive shaft locking device to secure the upper rotor connecting device.

[0017] Compared with the prior art, the main drive shaft assembly and manufacturing method for a coaxial twin-rotor tip jet system provided by the present invention have at least the following beneficial effects.

[0018] 1. The main drive shaft assembly of the present invention has high coaxiality and high mechanical strength, providing reliable support and transmission function for the upper rotor of the coaxial twin-rotor tip jet system.

[0019] 2. During the manufacturing process, alloy structural steel is used to manufacture the main drive shaft, and the component materials are heat-treated to improve their hardness, resulting in high mechanical strength and corrosion resistance. This meets the standard of supporting the upper rotor and transmission as a support component, providing strong rigidity and enabling reliable coaxial twin rotor tip jet power transmission.

[0020] 3. The main drive shaft of this invention has a hollow, slender shaft structure formed by deep drilling, used to transport cool air within the main drive shaft, thereby achieving heat dissipation and improving the temperature resistance of the main drive shaft to ensure normal operation under high temperature and high pressure conditions. The hollow, long shaft structure of the main drive shaft also helps to ensure the position of the transmission mechanism and the distance between the upper and lower rotors. Furthermore, the hollow shaft structure of the main drive shaft also helps to reduce the weight of the transmission mechanism and improve transmission efficiency.

[0021] 4. The main drive shaft assembly of the present invention also includes an end anti-loosening locking device for locking with the upper rotor connecting disc to ensure a stable connection between the upper rotor and the main drive shaft, thereby ensuring the stability and reliability of the main drive shaft assembly during operation.

[0022] 5. In the main drive shaft assembly of the present invention, by providing a shaft with a length range of 1.4-1.6m, space is reserved in its extension direction for the installation and operation of the lower rotor, thereby ensuring the normal installation and operation of the dual rotor system.

[0023] 6. In the main drive shaft assembly of the present invention, by setting the outer diameter of the shaft body in the range of 45-50mm, it is convenient to install and cooperate with the external outer tube, and by setting the inner diameter of the shaft body in the range of 35-40mm, it is ensured that sufficient cooling air can flow through the interior to provide a sufficient cooling effect. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly introduced below. The features and advantages of the present invention can be more clearly understood by referring to the accompanying drawings. The accompanying drawings are schematic and should not be construed as limiting the present invention in any way. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a front view of the main drive shaft assembly for a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention.

[0026] Figure 2a This is a partial isometric view of the upper part of the main drive shaft assembly for a coaxial twin-rotor tip jet system according to an embodiment of the present invention.

[0027] Figure 2b This is a partial isometric view of the lower part of the main drive shaft assembly for a coaxial twin-rotor tip jet system according to an embodiment of the present invention.

[0028] Figure 3a This is a partial front view of the upper part of the main drive shaft in the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention.

[0029] Figure 3b This is a partial front view of the lower part of the main drive shaft in the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention.

[0030] Figure 4a This is a partial cross-sectional view of the upper part of the main drive shaft in the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention.

[0031] Figure 4b This is a partial cross-sectional view of the lower part of the main drive shaft in the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention.

[0032] Figure 5 This is a cross-sectional view of the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention, after assembly with an external hot airflow duct and a gearbox housing.

[0033] Figure 6a This is a partial sectional view of the upper part of the main drive shaft assembly for a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention, after assembly with an external hot airflow duct and a gearbox housing.

[0034] Figure 6b This is a partial sectional view of the lower part of the main drive shaft assembly of a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention, after assembly with an external hot airflow duct and a gearbox housing.

[0035] Figure label: 1-Main drive shaft locking device; 11-Main drive shaft locking upper nut; 12-Main drive shaft locking lower nut; 2-Upper rotor connecting device; 21-Upper rotor connecting plate; 22-Connecting plate sealing plate; 23-Upper rotor connecting screw; 3-Main drive shaft; 30-Shaft body; 31-Connecting plate spline; 32-Main drive shaft sealing assembly upper positioning part; 33-Main shaft driven gear connecting flange; 34-Main drive shaft sealing assembly lower positioning part; 35-Main shaft driven gear screw connecting positioning part; 36-Flange connecting weld. 37-Large diameter flow channel inside the main drive shaft; 38-Small diameter flow channel inside the end of the main drive shaft; 4-Main shaft driven gear assembly; 41-Main shaft driven gear; 42-Main shaft driven gear connecting screw; 50-Main drive shaft sleeve; 60-Main drive shaft hot air sleeve; 61-Main drive shaft hot air passage; 62-Main drive shaft hot air inlet; 71-Gearbox top cover; 72-Gearbox housing; 82-Main drive shaft upper sealing assembly; 84-Main drive shaft lower sealing assembly; 91-Upper support base; 92-Lower support base. Detailed Implementation

[0036] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0038] The following detailed description, with reference to the accompanying drawings, illustrates a main drive shaft assembly and manufacturing method for a coaxial dual-rotor tip jet system according to an embodiment of the present invention. This assembly connects the upper rotor of a coaxial dual-rotor tip jet aircraft to the fuselage, providing support and transmission functions for the upper rotor. The coaxial dual-rotor tip jet aircraft can be a manned helicopter, a drone, or the like.

[0039] like Figure 1 As shown, the main drive shaft assembly for a coaxial twin-rotor tip jet system provided according to an embodiment of the present invention provides support and transmission functions for the upper rotor of a coaxial twin-rotor tip jet aircraft. It includes: a main drive shaft 3 with a hollow structure; an upper rotor connecting device 2, disposed at the upper end of the main drive shaft 3, connecting the main drive shaft 3 to the upper rotor; a main drive shaft locking device 1, disposed at the upper end port (i.e., the upper end) of the main drive shaft 3 and located above the upper rotor connecting device 2, providing an end-locking function to prevent loosening; and a main shaft driven gear assembly 4, disposed at the lower end of the main drive shaft 3, providing driving force from the power system to the main drive shaft 3. The hollow structure of the main drive shaft 3 allows cooling air to pass through, cooling the main drive shaft 3 as high-temperature, high-pressure gas flows past the outside of the main drive shaft 3 to drive the rotor. The main drive shaft 3, the upper rotor connecting device 2, and the main shaft driven gear assembly 4 may have a common central axis to achieve reliable assembly and transmission. Furthermore, the length of the main drive shaft 3 can be set to a range of 1.4-1.6m to meet the installation and operation requirements of the upper rotor.

[0040] In this embodiment, the upper rotor can be connected to the fuselage of the coaxial twin-rotor tip jet aircraft via the main drive shaft assembly. The upper rotor is driven in two ways: one is by receiving driving force from the power system via the main shaft driven gear assembly 4, which rotates the main drive shaft 3 and transmits it to the upper rotor via the upper rotor connecting device 2; the other is by receiving high-temperature hot air (high-temperature, high-pressure combustion gas used as jet airflow) at the lower end of the main drive shaft hot airflow channel 61 formed between the main drive shaft 3 and the main drive shaft hot air sleeve 60, and supplying it to the airflow channel in the upper rotor from the upper end outlet. The airflow is then ejected from the tip of the upper rotor, creating a counter-thrust that drives the upper rotor to rotate, thus achieving jet propulsion for the upper rotor. During the high-temperature hot air jet propulsion process, cooling airflow can be provided to the main drive shaft 3 through its hollow structure. It should be understood that, as needed, both of the above driving methods can be used simultaneously to drive the upper rotor in the coaxial twin-rotor tip jet system. Optionally, the main drive shaft assembly is connected and fixed to the upper rotor via the upper rotor connecting plate 21 of the upper rotor connecting device 2. The main drive shaft assembly is also engaged with the gearbox in the fuselage via the main shaft driven gear assembly 4, thereby providing transmission from the power system to the upper rotor.

[0041] like Figures 3a to 4b As shown, the main drive shaft 3 may include: a longitudinally extending shaft body 30 with a hollow interior; a connecting disc spline 31 located at the upper end of the shaft body 30 for connection with the upper rotor connecting device 2; and a main shaft driven gear connecting flange 33 located at the lower end of the shaft body 30, on which a main shaft driven gear screw connecting positioning part 35 is formed for connection with the main shaft driven gear assembly 4. The main drive shaft 3 may also include: an upper positioning part 32 and a lower positioning part 34 of the main drive shaft sealing assembly located at the lower end of the shaft body 30, which are formed into an outwardly protruding annular tooth structure for fitting and installing a brush-type sealing structure to provide a sealing function for the external hot air flow path and the power system lubricating oil. Optionally, a large-diameter flow channel 37 and a small-diameter flow channel 38 are formed inside the shaft body 30 to provide a cooling air flow path. Optionally, the shaft body 30 may have a structure with a closed upper end and an open lower end to receive cooling air from the lower end. Further, as Figure 4b As shown, the main drive shaft 3 may also include a flange connection weld 36 at its lower end for welding the main shaft driven gear connection flange 33 to connect the main shaft driven gear connection flange 33 to the main drive shaft 3. The main shaft driven gear 41 and the main shaft driven gear connection flange 33 are connected by screws, which can pass through the main shaft driven gear screw connection positioning part 35 for fixing. Optionally, the outer diameter of the shaft body 30 of the main drive shaft 3 can be set to a range of 45-50mm, the inner diameter to a range of 35-40mm, and the wall thickness to a range of 4.5-7mm.

[0042] like Figure 4a As shown, the small-diameter flow channel 38 at the end of the main drive shaft is located above the large-diameter flow channel 37 and is connected to it. Furthermore, the radial diameter of the small-diameter flow channel 38 at the end of the main drive shaft can be smaller than the radial diameter of the large-diameter flow channel 37. The upper end dimension of the main drive shaft 3 is slightly reduced to accommodate the spline shape and to cooperate with the upper rotor connecting device 2. Therefore, a small-diameter flow channel 38 with a smaller diameter is formed in this part to ensure the thickness of the shaft wall and the strength of the shaft body. Optionally, the diameter of the large-diameter flow channel 37 can be set to a range of 35-40 mm, and the diameter of the small-diameter flow channel 38 at the end of the main drive shaft can be set to a range of 25-30 mm. The lower opening of the large-diameter flow channel 37 inside the main drive shaft is used to receive cooling air from the cooling air supply device. This cooling air flows through the large-diameter flow channel 37 and the small-diameter flow channel 38 at the end of the main drive shaft, providing cooling to the main drive shaft 3. The air can then be discharged from the upper opening of the small-diameter flow channel 38 at the end of the main drive shaft. Optionally, the shaft body 30 of the main drive shaft 3 can be made of alloy structural steel, and more specifically, 35CrMo, to provide excellent comprehensive mechanical properties and temperature and corrosion resistance, achieving reliable power transmission and good thermal stability under high-temperature jet gas flow conditions. See also Figure 3b Optionally, the upper positioning part 32 and the lower positioning part 34 of the main drive shaft sealing assembly located at the lower end of the shaft body 30 are respectively located on the upper and lower sides of the main shaft driven gear connecting flange 33, and are used to cooperate with the main drive shaft sealing assembly to form a brush seal structure with upper and lower layers, thereby realizing a dual sealing function.

[0043] See Figure 2aThe upper rotor connecting device 2 may include: an upper rotor connecting plate 21 connected to the connecting plate spline 31 of the main drive shaft 3; a connecting plate sealing plate 22 fixed on the upper side of the upper rotor connecting plate 21; and a plurality of upper rotor connecting screws 23 disposed on the connecting plate sealing plate 22 for tightening to the mounting part of the upper rotor, thereby realizing the assembly of the main drive shaft assembly and the upper rotor. Optionally, the plurality of upper rotor connecting screws 23 are evenly distributed on the connecting plate sealing plate 22 to provide a uniform force distribution between the connecting parts. Further, the outer diameter of the upper rotor connecting plate 21 may be set to a range of 230-250 mm, and the inner diameter may be set to a range of 45-50 mm, so as to fit tightly with the connecting plate spline 31 of the shaft body 30. Optionally, the outer diameter of the connecting plate sealing plate 22 may be the same as that of the upper rotor connecting plate 21, and the inner diameter of the connecting plate sealing plate 22 may be slightly larger than that of the upper rotor connecting plate 21. The upper rotor connecting disc 21 and connecting disc sealing plate 22 of this size enable a secure connection between the main drive shaft and the upper rotor. Furthermore, the upper rotor connecting screws 23 can be arranged in a coaxial ring configuration, with 2-4 turns from the inside out, on the connecting disc sealing plate 22. Even further, adjacent turns of the upper rotor connecting screws 23 can be radially staggered, or the upper rotor connecting screws 23 within the same turn can be spaced equidistantly in the circumferential direction. See also... Figure 2a In this embodiment, the upper rotor connecting screws 23 are arranged in a ring shape in layout 3. This method achieves a stable assembly of the main drive shaft assembly and the upper rotor, and ensures uniform force distribution on the connecting parts.

[0044] like Figure 1 and Figure 2a As shown, the main drive shaft locking device 1 may include: a main drive shaft locking upper nut 11 and a main drive shaft locking lower nut 12 disposed at the upper end port of the shaft body 30 of the main drive shaft 3. By rotating the main drive shaft locking upper nut 11 and the main drive shaft locking lower nut 12 isotropically to the upper end port of the shaft body 30, the upper rotor connecting plate 21 of the lower upper rotor connecting device 2 is clamped and fixed to the main drive shaft 3.

[0045] like Figure 2b As shown, the spindle driven gear assembly 4 may include: a spindle driven gear 41 and a plurality of spindle driven gear connecting screws 42 disposed thereon; the spindle driven gear 41 is connected to the spindle driven gear connecting flange 33 by tightening the spindle driven gear connecting screws 42 to the spindle driven gear screw connecting positioning part 35, thereby realizing the transmission of power received from the power system to the main drive shaft 3. Optionally, the plurality of spindle driven gear connecting screws 42 are arranged on the spindle driven gear 41 at even intervals.

[0046] like Figure 2a and 3aAs shown, the upper rotor connecting plate 21 of the upper rotor connecting device 2 is connected to the main drive shaft 3 via the connecting plate spline 31, and is locked by the main drive shaft locking upper nut 11 and main drive shaft locking lower nut 12 on the main drive shaft locking device 1 to achieve the end anti-loosening locking function; after the connecting plate sealing plate 22 is coaxially engaged with the upper rotor connecting plate 21, it is connected to the upper rotor via the upper rotor connecting screw 23, so that the power is transmitted from the main drive shaft 3 to the upper rotor through the upper rotor connecting plate 21.

[0047] Furthermore, such as Figure 5 , Figure 6a and Figure 6b As shown, in another embodiment, the main drive shaft assembly may further include a main drive shaft hot air sleeve 60 disposed outside the main drive shaft 3, forming a main drive shaft hot air passage 61 between the main drive shaft 3 and the main drive shaft hot air sleeve 60. Optionally, a main drive shaft hot air inlet 62 may be provided on the lower side wall of the main drive shaft hot air sleeve 60 for connecting to a hot air supply pipe to introduce hot air from below.

[0048] like Figure 6a and Figure 6b As shown, the main drive shaft assembly may further include a main drive shaft sleeve 50 covering the outer periphery of the main drive shaft 3 to prevent hot air flowing from the outside of the main drive shaft 3 from directly contacting the main drive shaft 3 and causing it to be corroded by combustion gases. Optionally, the main drive shaft sleeve 50 may be tightly fitted and covered on the outer peripheral surface of the main drive shaft 3. Thus, hot air flows between the main drive shaft hot air sleeve 60 and the main drive shaft sleeve 50 in the main drive shaft hot air passage 61. Optionally, the main drive shaft hot air sleeve 60 may be welded to the upper support base 91, the upper support base 91 and the lower support base 92 may be welded together, the lower support base 92 may be fixed to the gearbox cover 71 by screws, the gearbox cover 71 and the gearbox housing 72 may be connected by screws, and the gearbox is part of the power system.

[0049] Furthermore, such as Figure 5 , Figure 6b As shown, the upper sealing assembly 82 and the lower sealing assembly 84 of the main drive shaft are respectively assembled onto the upper positioning part 32 and the lower positioning part 34 of the main drive shaft sealing assembly to form a brush seal structure, which prevents lubricating oil leakage in the gearbox and also prevents hot air from flowing into the gearbox through the gap at the connection.

[0050] Specifically, during operation, when the transmission drive is used, the main shaft driven gear 41 of the main shaft driven gear assembly 4 receives driving force from the power system, and drives the shaft body 30 of the main drive shaft 3 to rotate through the main shaft driven gear connecting flange 33. The upper end of the main drive shaft 3 is connected to the upper rotor connecting disc 21 through the connecting disc spline 31, which drives the connecting disc sealing plate 22 of the upper rotor connecting device 2 to rotate. Then, the upper rotor is driven to rotate through the upper rotor connecting screw 23 tightened to the mounting part of the upper rotor on the connecting disc sealing plate 22. During operation, when jet drive is used, the lower air inlet of the main drive shaft hot air passage 61 formed between the shaft body 30 of the main drive shaft 3 and the hot air sleeve 60 of the main drive shaft receives high-temperature hot air and provides it to the air passage in the upper rotor from the upper air outlet. Finally, it is ejected from the tip of the upper rotor. The ejected hot air flow forms a counter-thrust force on the upper rotor, which drives the upper rotor to rotate, thereby realizing jet drive of the upper rotor. During jet drive, the upper positioning part 32 and the lower positioning part 34 of the main drive shaft sealing assembly at the lower end of the shaft body 30 of the main drive shaft 3 provide a sealing function for the jet air flow; and the lower opening of the large-diameter flow passage 37 inside the shaft body 30 of the main drive shaft receives cooling air and allows the cooling air flow to pass through the hollow structure to provide a cooling function.

[0051] The above implementation method realizes a main drive shaft assembly for a coaxial twin-rotor tip jet system, which improves thermal stability by internally supplying cooling air, provides reliable support and transmission functions, and also has an end locking function.

[0052] According to another embodiment of the present invention, a method for manufacturing a main drive shaft assembly for a coaxial twin-rotor tip jet system is provided, which may include the following steps.

[0053] S1: Machining and preparing the main drive shaft 3, including obtaining an elongated mandrel made of alloy structural steel; machining a flange connection weld 36 on the mandrel; welding a main shaft driven gear connection flange 33; drilling holes to form a large-diameter flow channel 37 inside the main drive shaft and a small-diameter flow channel 38 at the end of the main drive shaft; and turning to form the shaft body 30 of the main drive shaft 3. This step may also include turning to form an upper positioning part 32 and a lower positioning part 34 of the main drive shaft sealing assembly located above and below the main shaft driven gear connection flange 33, respectively; machining a main shaft driven gear screw connection positioning part 35; and milling a connecting disc spline 31. Specifically, this may include the following steps.

[0054] For the machining of the main drive shaft 3, it is necessary to ensure high coaxiality of the shaft body 30, that is, to ensure that the shaft body 30 extends along a straight line without deviation, thereby ensuring transmission accuracy. Also, since the shaft body 30 is a hollow structure with cooling air channels, it is necessary to prevent the collapse of the thin-walled structure during machining. To achieve these objectives, the main drive shaft uses high-strength materials, such as 35CrMo, and undergoes heat treatment to ensure mechanical and machining strength. Furthermore, to ensure the coaxiality of the main drive shaft 3 and avoid secondary clamping during machining, since the inner and outer diameters are machined on a CNC lathe, a thin-walled structure has been formed. Therefore, it is necessary to ensure the coaxiality of the shaft body 30 and prevent the collapse of the thin-walled structure. A horizontal machining center is used to mill the spindle driven gear screw connection positioning part 35. A four-axis machining center will not affect the coaxiality; therefore, a four-axis machining center is used to machine the connecting disc spline 31.

[0055] S1.1: Provide the material for the main drive shaft 3 and manufacture an elongated mandrel. Regarding the selection of the material for the main drive shaft 3, considering the large torque it bears and the need for good high-temperature strength, alloy structural steel is preferred to reduce deformation at high temperatures and ensure the working stability of the main drive shaft in the coaxial twin-rotor tip jet system. Furthermore, 35CrMo, which has good comprehensive mechanical properties and temperature resistance, can be used as the shaft material for the main drive shaft 3.

[0056] S1.2: Use a CNC lathe to machine a flange connection weld 36 at the bottom of the mandrel, which is used to weld the spindle driven gear connection flange 33.

[0057] S1.3: The prepared spindle driven gear connecting flange 33 is welded to the lower end of the mandrel by argon arc welding.

[0058] S1.4: Perform heat treatment on the processed mandrel. For example, a high-frequency furnace can be used for heat treatment and tempering to HRC28-32 to further improve the material strength. In this step, the quenching temperature can be set to 850℃ and the tempering temperature to 550℃, using water cooling or oil cooling. Specifically, quenching can be performed at around 850℃, followed by heating and holding at this temperature for a certain time, and then rapid cooling using oil as the cooling medium. The tempering temperature can be set to 550℃, held for 2-4 hours, and then allowed to cool naturally.

[0059] In this embodiment, the strength and rigidity of the main drive shaft are ensured through the above steps S1.1-1.4.

[0060] S1.5: Deeply drill a hole in the heat-treated mandrel to machine the large-diameter flow channel 37 inside the main drive shaft. Perform a diameter-reducing opening treatment at the upper end of the mandrel to machine the small-diameter flow channel 38 at the end of the main drive shaft, realizing the function of internal cooling air passage. Further, the diameter of the large-diameter flow channel 37 inside the main drive shaft is in the range of 35-40mm, and the diameter of the small-diameter flow channel 38 at the end of the main drive shaft is in the range of 25-30mm.

[0061] S1.6: Using a CNC lathe with two centers for clamping, the mandrel after deep drilling is clamped. The outside of the mandrel is machined according to the outer diameter requirements of the main drive shaft 3, as well as the outer diameter and positioning requirements of the rotor connecting plate (connecting plate spline 31), to obtain the shaft body 30. In this step, the upper positioning part 32 and the lower positioning part 34 of the main drive shaft sealing assembly, located above and below the main drive shaft driven gear connecting flange 33, can also be machined on the shaft body 30. Further, the outer diameter of the shaft body 30 obtained by machining is in the range of 45-50mm.

[0062] S1.7: A horizontal machining center is used to mill a spindle driven gear screw connection positioning part 35 on the driven gear connection flange 33 for connecting the spindle driven gear 41 to the spindle driven gear connection flange 33. Optionally, the spindle driven gear screw connection positioning part 35 may be an opening for mounting screws arranged on the driven gear connection flange 33.

[0063] S1.8: Use a four-axis machining center to mill the spline 31 of the connecting disc on the upper end of the shaft 30 to obtain the main drive shaft 3. The milled spline 31 of the connecting disc is used for assembly and positioning with the upper rotor connecting disc 21.

[0064] S1.9: The main drive shaft 3 is machined to remove burrs, blunt the sharp edges, and smooth the sharp edges of the surface.

[0065] In this embodiment, after machining the flow channel, the above steps S1.5-1.9 reduce the number of clamping operations on the main drive shaft to be machined, thereby ensuring coaxiality. Using a CNC lathe to machine the outer diameter and end face of the shaft provides high external turning efficiency. By employing a CNC lathe with two centers for clamping, workpiece clamping deformation can be effectively reduced, further ensuring accuracy and stability, and simplifying tooling. A horizontal machining center is used to mill the flange thread holes, and the four-axis machining center does not affect coaxiality, thus ensuring coaxiality and preventing the collapse of thin-walled structures.

[0066] Optionally, the main drive shaft can be machined and formed in the following ways: 1) Using a CNC lathe, a weld joint is machined at one end of the mandrel. This weld joint is used for welding between the mandrel and the flange, so a joint position also needs to be machined on the flange; 2) The flange and mandrel are welded using argon arc welding; 3) The welded mandrel and flange are heat-treated and tempered to HRC28-32 using a high-frequency furnace to improve material strength; 4) A deep hole is drilled to machine the internal cold air flow channel, considering that the other end of the drive shaft needs to be connected to the upper rotating shaft. 5) The material after deep drilling is machined using a CNC lathe to machine the outer diameter of the main drive shaft, the outer diameter of the rotor connecting plate, and the positioning, and to machine the sealing device for the upper and lower flange connection; 6) The flange thread hole is milled by a horizontal machining center to connect the spindle driven gear to the flange; 7) The spline is milled by a four-axis machining center to assemble and position the upper rotor connecting plate; 8) The burrs are removed by clamping, and the sharp edges are blunted to make the sharp edges of the object surface smooth.

[0067] The main drive shaft 3 obtained through the above process has high coaxiality, temperature resistance, corrosion resistance and mechanical strength.

[0068] S2: Assemble the prepared main drive shaft 3 with the pre-prepared main drive shaft locking device 1, upper rotor connecting device 2, and main shaft driven gear assembly 4 to obtain the main drive shaft assembly for a coaxial twin-rotor tip jet system. Optionally, the main drive shaft locking device 1, upper rotor connecting device 2, and main shaft driven gear assembly 4 can be selected from existing accessories as needed, or can be prepared in a conventional manner. Further, this step may specifically include the following steps.

[0069] S2.1: The main shaft driven gear 41 of the main shaft driven gear assembly 4 is welded to the driven gear connecting flange 33.

[0070] S2.2: Assemble the upper rotor connecting plate 21 with the connecting plate spline 31 at the upper end of the main drive shaft, and use the main drive shaft locking device 1 and the connecting plate spline 31 to lock the upper rotor connecting plate 21 and the connecting plate sealing plate 22.

[0071] Optionally, step S2 may also include installing an upper sealing assembly 82 and a lower sealing assembly 84 on the lower part of the main drive shaft 3 at the upper positioning part 32 and the lower positioning part 34 of the main drive shaft sealing assembly, respectively, to prevent the lubricating oil in the sealed gearbox body from leaking into the hot air passage 61 of the main drive shaft, and to avoid the lubrication efficiency reduction caused by the increase in lubricating oil temperature due to the infiltration of hot air into the gearbox.

[0072] All of the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of the present invention, and will not be described in detail here.

[0073] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0074] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order and method of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0075] It should be understood that the foregoing only illustrates some embodiments, and changes, modifications, additions, and / or variations can be made without departing from the scope and spirit of the disclosed embodiments. These embodiments are illustrative and not restrictive. Furthermore, the described embodiments relate to those currently considered most practical and preferred, and should be understood as not being limited to the disclosed embodiments, but rather intended to cover different modifications and equivalent arrangements included within the spirit and scope of those embodiments. Moreover, the various embodiments described above can be used in conjunction with other embodiments; for example, an aspect of one embodiment can be combined with an aspect of another embodiment to achieve yet another embodiment. Additionally, individual features or components of any given component can constitute another embodiment.

[0076] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A main drive shaft assembly for a coaxial twin-rotor tip jet system, characterized in that, Used to connect the upper rotor of a coaxial twin-rotor tip jet aircraft to the fuselage, providing support and transmission functions for the upper rotor, including: The main drive shaft (3) includes a shaft body (30) extending longitudinally and having a hollow internal channel, a connecting disc spline (31) located at the upper end of the shaft body (30), and a main shaft driven gear connecting flange (33) located at the lower end of the shaft body (30), wherein the hollow internal channel of the shaft body (30) of the main drive shaft (3) serves as a cooling air channel; The upper rotor connecting device (2) is located at the upper end of the main drive shaft (3) and connected to the connecting disc spline (31) for connecting the main drive shaft (3) and the upper rotor; The main drive shaft locking device (1) is set at the upper end port of the main drive shaft (3) and located on the upper rotor connecting device (2) to lock the upper rotor connecting device (2) to the main drive shaft (3). The main shaft driven gear assembly (4) is located at the lower end of the main drive shaft (3) and connected to the main shaft driven gear connecting flange (33), and is used to receive driving force from the power system; The main drive shaft (3), the upper rotor connecting device (2), and the main shaft driven gear assembly (4) are coaxially arranged.

2. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 1, characterized in that, The length of the shaft body (30) of the main drive shaft (3) ranges from 1.4 to 1.6 m, the outer diameter ranges from 45 to 50 mm, and the inner diameter ranges from 35 to 40 mm.

3. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 1, characterized in that, The internal hollow channel of the shaft body (30) of the main drive shaft (3) is composed of a large-diameter flow channel (37) inside the main drive shaft and a small-diameter flow channel (38) at the end of the main drive shaft; Among them, the position of the small diameter flow channel (38) at the end of the main drive shaft corresponds to the position of the spline (31) of the connecting disc; the small diameter flow channel (38) at the end of the main drive shaft is located at the upper end of the large diameter flow channel (37) in the main drive shaft and is connected to each other; the radial diameter of the small diameter flow channel (38) at the end of the main drive shaft is smaller than the radial diameter of the large diameter flow channel (37) in the main drive shaft.

4. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 1, characterized in that, The main drive shaft (3) also includes: The upper positioning part (32) and the lower positioning part (34) of the main drive shaft sealing assembly are located at the lower end of the shaft body (30) and are respectively located above and below the main shaft driven gear connecting flange (33) for mounting the brush seal structure.

5. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 1, characterized in that, The upper rotor connecting device (2) includes: The upper rotor connecting plate (21) is connected to the connecting plate spline (31) of the main drive shaft (3); The connecting disc sealing plate (22) is fixed on the upper side of the upper rotor connecting disc (21); Multiple upper rotor connecting screws (23) are provided on the connecting disc sealing plate (22) for tightening to the mounting part of the upper rotor.

6. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 5, characterized in that, The outer diameter of the upper rotor connecting plate (21) ranges from 230 to 250 mm; The outer diameter of the connecting disc sealing plate (22) is the same as that of the upper rotor connecting disc (21); The upper rotor connecting screw (23) is arranged in a coaxial ring pattern with 2-4 turns from the inside to the outside on the connecting disc sealing plate (22).

7. The main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 5, characterized in that, The main drive shaft locking device (1) includes: The upper nut (11) and lower nut (12) of the main drive shaft are locked in an isotropic manner to the upper end port of the shaft body (30), and the upper rotor connecting plate (21) of the lower rotor connecting device (2) is clamped and fixed to the main drive shaft (3).

8. A method for manufacturing a main drive shaft assembly for a coaxial twin-rotor tip jet system, characterized in that, include: S1: Machining and preparing the main drive shaft (3), including making a long mandrel using alloy structural steel; machining a flange connection weld (36) on the mandrel, welding the main shaft driven gear connection flange (33), drilling to form a large-diameter flow channel (37) inside the main drive shaft and a small-diameter flow channel (38) at the end of the main drive shaft, turning to form the shaft body (30) of the main drive shaft (3), machining the main shaft driven gear screw connection positioning part (35), and milling the connecting disc spline (31); S2: Assemble the prepared main drive shaft (3) with the pre-prepared main drive shaft locking device (1), upper rotor connecting device (2), and main shaft driven gear assembly (4) to obtain the main drive shaft assembly for the coaxial dual rotor tip jet system.

9. The method for manufacturing the main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 8, characterized in that, S1 includes: S1.1: Using 35CrMo as the shaft material of the main drive shaft (3), a long mandrel is made; S1.2: Use a CNC lathe to machine a flange connection weld (36) at the bottom of the mandrel. S1.3: The pre-prepared spindle driven gear connecting flange (33) is welded to the lower end of the mandrel by argon arc welding; S1.4: Heat treat the processed mandrel; S1.5: Deeply drill holes in the heat-treated mandrel to machine the large-diameter flow channel (37) inside the main drive shaft, and perform a variable-diameter opening process at the upper end of the mandrel to machine the small-diameter flow channel (38) inside the end of the main drive shaft to form an internal cooling gas channel. S1.6: The outer diameter of the mandrel after deep drilling is machined by CNC lathe to obtain shaft (30), and the outer diameter of the machined shaft (30) is not greater than 50mm; S1.7: Using a horizontal machining center, mill the spindle driven gear screw connection positioning part (35) on the driven gear connecting flange (33). S1.8: Use a four-axis machining center to mill the spline (31) of the connecting disc on the upper end of the shaft (30) to obtain the main drive shaft (3); S1.9: The main drive shaft (3) is machined to remove burrs, blunt the sharp edges, and smooth the sharp edges of the surface.

10. The method for manufacturing the main drive shaft assembly for a coaxial twin-rotor tip jet system according to claim 8, characterized in that, S2 include: S2.1: The spindle driven gear (41) of the spindle driven gear assembly (4) is welded to the driven gear connecting flange (33); S2.2: Assemble the upper rotor connecting plate (21) of the upper rotor connecting device (2) with the connecting plate spline (31) at the upper end of the main drive shaft (3), and lock the upper rotor connecting plate (21) to the main drive shaft (3) through the main drive shaft locking device (1) to secure the upper rotor connecting device (2).

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