A high torque tightening tool and method for a helicopter inner rotor shaft nut

Abstract

The application belongs to the technical field of aviation assembly, and discloses a large torque tightening tool and method for a nut of an inner rotor shaft of a helicopter. The tool comprises a quick-change disc assembly, a large torque tightening assembly and an inner rotor shaft flexible assembly. The quick-change disc assembly is used to be connected with an external actuator and to realize quick change. The large torque tightening assembly realizes accurate tightening of the nut through a servo motor, a hollow speed reducer and a dynamic torque sensor. The inner rotor shaft flexible assembly penetrates through the hollow speed reducer and is used to be connected with a spline of the inner rotor shaft to provide a counter torque. The core is that the tightening torque and the counter torque are transmitted together and fixed in the same hollow speed reducer mounting seat to offset each other, form torque internal circulation and greatly reduce the requirement for a support structure. Through coaxial integrated design, the application realizes synchronous alignment of the inner rotor shaft rotation stopping and the nut tightening, simplifies the centering operation, improves the assembly efficiency and accuracy, and has flexible buffering and modular quick change capacity.

Description

Technical Field

[0001] This invention belongs to the field of aviation assembly technology, and in particular relates to a high-torque tightening tool and method for a helicopter internal rotor shaft nut. Background Technology

[0002] After installing a bearing for the internal rotor shaft of a helicopter main gearbox, a nut needs to be installed to prevent the bearing from coming off. According to the installation process requirements, a certain torque needs to be controlled when tightening the nut. A conventional approach typically involves designing a clamping fixture for the internal rotor shaft at the bottom and a nut tightening fixture at the top. This approach has the following disadvantages: the upper and lower fixtures require extremely high concentricity, making adjustment difficult; during high-torque tightening, the enormous reaction force needs to be borne by an external support structure, resulting in extremely high requirements for the strength and rigidity of the support structure, increasing the complexity and cost of the fixture; and assembly efficiency is low. Summary of the Invention

[0003] The purpose of this invention is to provide a high-torque tightening fixture and method for helicopter internal rotor shaft nuts, so as to solve the above-mentioned technical problems.

[0004] To solve the above-mentioned technical problems, the specific technical solution of the present invention, a high-torque tightening fixture and method for helicopter internal rotor shaft nuts, is as follows: A high-torque tightening fixture for a helicopter internal rotor shaft nut includes a quick-change disc assembly, a high-torque tightening assembly, and an internal rotor shaft flexible assembly. The quick-change disc assembly is used to suspend and connect the entire fixture to an external device. The quick-change disc assembly and the high-torque tightening assembly are connected via a zero-point positioner. The high-torque tightening assembly and the internal rotor shaft flexible assembly are jointly fixed on the hollow reducer mounting base of the high-torque tightening assembly and share the same axis. The tightening torque of the high-torque tightening assembly and the reaction torque of the internal rotor shaft flexible assembly are jointly transmitted to the hollow reducer mounting base and cancel each other out.

[0005] Furthermore, the quick-change disc assembly includes a tooling docking quick-change disc, a quick-change welding frame, a zero-point locator female head, and a tightening component quick-change disc. The tooling docking quick-change disc is fixedly installed above the quick-change welding frame. The zero-point locator female head and the tightening component quick-change disc are fixed on one side of the quick-change welding frame. The tooling docking quick-change disc is used to connect with an external actuator. The zero-point locator female head mates with the zero-point locator male head of the high-torque tightening component. The tightening component quick-change disc realizes the connection and quick-change function with the high-torque tightening component. The tooling docking quick-change disc and the tightening component quick-change disc integrate an electrical interface and a pneumatic interface.

[0006] Furthermore, the high-torque tightening assembly includes a second quick-change welding bracket, a quick-change tightening assembly disc, a zero-point positioner male connector, a hollow reducer, an inner rotor shaft nut fixture, a hollow reducer mounting base, a high-torque dynamic torque sensor, and a servo motor. The hollow reducer is mounted on the hollow reducer mounting base, and the inner rotor shaft nut fixture is installed at the output end of the hollow reducer. The output of the servo motor is connected to the input end of the hollow reducer through the high-torque dynamic torque sensor. The second quick-change welding bracket is fixedly installed on the... Above the hollow reducer mounting base, the tightening assembly quick-change disc and the zero-point locator male are fixedly installed on one side of the quick-change welding frame 2. The zero-point locator male is connected to the zero-point locator female of the quick-change disc assembly to achieve precise positioning of the high-torque tightening assembly and the quick-change disc assembly. The tightening assembly quick-change disc female is connected to the tightening assembly quick-change disc male of the quick-change disc assembly to achieve connection and quick change of the high-torque tightening assembly 2 and the quick-change disc assembly 1. The inner rotor shaft nut fixture is fixedly installed below the hollow reducer mounting base.

[0007] Furthermore, the flexible internal rotor shaft assembly is mounted on the hollow reducer mounting base together with the hollow reducer through the hollow part of the hollow reducer.

[0008] Furthermore, the flexible inner rotor shaft assembly includes a component fixed shaft and an inner rotor shaft anti-rotation fixture. The upper end of the fixed shaft is fixedly mounted on the hollow reducer mounting base and is coaxial with the hollow reducer. The lower end of the fixed shaft is fixedly connected to the inner rotor shaft anti-rotation fixture, and the lower end of the inner rotor shaft anti-rotation fixture has an involute spline.

[0009] Furthermore, the flexible assembly of the inner rotor shaft also includes a shaft end cap, an upper assembly plate, a connecting shaft, a guide sleeve, and springs. The upper assembly plate is coaxially sleeved on the fixed shaft. The upper assembly plate and the anti-rotation fixture of the inner rotor shaft are connected by multiple connecting shafts. The upper end of the connecting shaft is limited by the shaft end cap. Multiple springs are respectively sleeved on the multiple connecting shafts. The upper end of the spring is provided with a guide sleeve. The guide sleeve is sleeved on the connecting shaft and fixedly connected to the upper assembly plate.

[0010] Furthermore, the flexible component of the inner rotor shaft passes through the hollow reducer, enabling the anti-rotation fixture of the inner rotor shaft and the nut fixture of the inner rotor shaft to be aligned synchronously.

[0011] This invention also discloses a method for tightening a nut on a helicopter internal rotor shaft, comprising the following steps: The tooling is installed onto an external actuator via a quick-change tray assembly; The anti-rotation fixture of the inner rotor shaft of the flexible assembly is connected to the spline of the inner rotor shaft. Adjust the tooling angle so that the inner rotor shaft nut tooling of the high torque tightening assembly aligns with the nut's bayonet. Start the servo motor and tighten the nut using closed-loop torque control; During the tightening process, the spring of the flexible component of the inner rotor shaft absorbs the axial displacement, and the tightening torque and the reaction torque cancel each other out in the hollow reducer mounting base.

[0012] The high-torque tightening fixture and method for helicopter internal rotor shaft nuts of the present invention have the following advantages: 1. Achieving internal torque circulation and self-balancing, significantly reducing reliance on external support: This invention creatively integrates a high-torque tightening component and an internal rotor shaft flexible component onto the same hollow reducer mounting base. During tightening, the tightening torque is transmitted to the mounting base through the hollow reducer, while the reaction torque is also transmitted to the same mounting base through the internal rotor shaft flexible component. These two torques form a couple within the mounting base and cancel each other out, fundamentally solving the problem of the huge reaction force needing to be borne by an external support structure in traditional solutions. This greatly reduces the strength and stiffness requirements for external actuators such as robots and gantry frames, simplifies the overall tooling system, and significantly reduces manufacturing costs.

[0013] 2. Significantly improved alignment accuracy and assembly efficiency: By designing the flexible component of the inner rotor shaft to run through the hollow reducer, the inner rotor shaft anti-rotation fixture and the inner rotor shaft nut fixture inherently possess extremely high concentricity. In actual operation, simply aligning the central inner rotor shaft anti-rotation fixture with the spline of the inner rotor shaft will automatically and synchronously align the outer nut fixture with the nut, achieving "one-time alignment, double positioning." This completely avoids the complex process of repeatedly adjusting the concentricity of the traditional upper and lower fixtures, simplifying the operation steps and increasing assembly efficiency by more than 50%.

[0014] 3. High-precision torque control to ensure assembly quality: A servo motor combined with a high-torque dynamic torque sensor forms a high-precision torque closed-loop control system. This system can monitor and control the tightening torque in real time and accurately, ensuring that every tightening strictly meets the process specifications, effectively avoiding the quality risks of over-tightening or under-tightening, and guaranteeing the reliability and safety of the connections of key components of the helicopter main gearbox from the process equipment level.

[0015] 4. Built-in flexible buffer mechanism to adapt to dynamic assembly process: The flexible assembly of the inner rotor shaft is designed with a flexible buffer structure consisting of springs and guide sleeves. This structure can effectively absorb the axial displacement generated during the tightening of the nut, thereby ensuring that the spline connection between the inner rotor shaft nut fixture and the nut, as well as between the inner rotor shaft anti-rotation fixture and the inner rotor shaft, always maintains good contact and stress state. This prevents jamming, wear, or accidental disengagement that may be caused by rigid contact, and improves the stability and reliability of the fixture during operation.

[0016] 5. Modular and quick-change design greatly enhances production line flexibility: The entire tooling, through the combination of the quick-change disc assembly and the zero-point positioner, achieves rapid positioning, connection, and replacement with external actuators. The integrated electrical and pneumatic interfaces of the quick-change disc enable instant power and signal connection. This modular design allows for the rapid deployment of different tooling on a single production line to adapt to different types or torque requirements for tightening bearing nuts, greatly improving the flexibility of the production line and equipment utilization, and meeting the characteristics of modern aviation's multi-variety, small-batch production.

[0017] 6. Simplified rotor shaft fixing method, making operation more convenient: By using an involute spline with a small module and many teeth as the connection method for the internal rotor shaft anti-rotation fixture, the operator only needs to fit the spline and rotate it by a small angle to complete the fit, which can withstand huge anti-torque. This method eliminates the complex and cumbersome external clamping fixtures of the traditional solution, making the operation lighter and faster, and further improving assembly efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the tooling described in this invention; Figure 2 This is a schematic diagram of the quick-change disc assembly of the present invention; Figure 3 This is a schematic diagram of the high-torque tightening assembly of the present invention; Figure 4 This is a schematic diagram of the internal rotor shaft flexible assembly of the present invention; Figure 5 This is a schematic cross-sectional view of the tooling structure of the present invention; The markings in the diagram are as follows: 1. Quick-change disc assembly; 2. High-torque tightening assembly; 3. Inner rotor shaft flexible assembly; 4. Tooling docking quick-change disc; 5. Quick-change welding bracket one; 6. Zero-point positioner female head; 7. Tightening assembly quick-change disc; 8. Quick-change welding bracket two; 9. Tightening assembly quick-change disc; 10. Zero-point positioner male head; 11. Hollow reducer; 12. Inner rotor shaft nut tooling; 13. Hollow reducer mounting base; 14. High-torque dynamic torque sensor; 15. Servo motor; 16. Assembly fixing shaft; 17. Shaft end cover; 18. Assembly upper plate; 19. Connecting shaft; 20. Guide sleeve; 21. Spring; 22. Inner rotor shaft anti-rotation tooling. Detailed Implementation

[0019] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, provides a high-torque tightening fixture and method for a helicopter internal rotor shaft nut.

[0020] like Figure 1 As shown, a high-torque tightening fixture for a helicopter internal rotor shaft nut according to the present invention includes a quick-change disc assembly 1, a high-torque tightening assembly 2, and an internal rotor shaft flexible assembly 3. The quick-change disc assembly 1 is used to suspend and connect the entire fixture to external equipment. The quick-change disc assembly 1 and the high-torque tightening assembly 2 are connected by a zero-point positioner. The high-torque tightening assembly 2 and the internal rotor shaft flexible assembly 3 are both fixed on the hollow reducer mounting base 13 of the high-torque tightening assembly 2 and share the same axis.

[0021] like Figure 2 As shown, the quick-change tray assembly 1 includes a tooling docking quick-change tray 4, a quick-change welding frame 5, a zero-point locator female head 6, and a tightening component quick-change tray male head 7. The tooling docking quick-change tray 4 is fixedly mounted above the quick-change welding frame 5, while the zero-point locator female head 6 and the tightening component quick-change tray male head 7 are fixed to one side of the quick-change welding frame 5. The tooling docking quick-change tray 4 is used to connect with external robots or gantry actuators, fulfilling the connection and quick-change function of high-torque tightening tooling. The zero-point locator female head 6 mates with the zero-point locator male head 10 of the high-torque tightening component 2, achieving precise positioning of the quick-change tray assembly 1 and the high-torque tightening component 2. The tightening component quick-change tray male head 7 enables connection and quick-change with the high-torque tightening component 2. The tooling quick-change disc 4 and the tightening assembly quick-change disc male connector 7 integrate electrical and pneumatic interfaces. The electrical interface provides power and communication for the components in the high-torque tightening assembly 2; the pneumatic interface supplies air to the zero-point positioner and meets the air supply needs of subsequent product expansion. The quick-change disc assembly 1 enables rapid and precise positioning and connection of the entire tooling with external actuators (via the zero-point positioner), and provides power, communication, and pneumatic power (through the quick-change disc), thereby enabling rapid tooling replacement and deployment on the production line, improving assembly flexibility and efficiency. The quick-change function of the quick-change disc can achieve the tightening process of bearing nuts with different requirements.

[0022] like Figure 3 As shown, the high-torque tightening assembly 2 includes a quick-change welding bracket 8, a quick-change female head 9, a zero-point positioner male head 10, a hollow reducer 11, an inner rotor shaft nut fixture 12, a hollow reducer mounting base 13, a high-torque dynamic torque sensor 14, and a servo motor 15. The hollow reducer 11 is mounted on the hollow reducer mounting base 13. The inner rotor shaft nut fixture 12 is installed at the output end of the hollow reducer 11. The inner rotor shaft nut fixture 12 is connected to the nut via a spline, and the nut is tightened by rotating the hollow reducer 11. The output of the servo motor 15 is connected to the input of the hollow reducer 11 via the high-torque dynamic torque sensor 14. The quick-change welding bracket 2 8 is fixedly installed above the hollow reducer mounting base 13. The tightening assembly quick-change disc female head 9 and the zero-point locator male head 10 are fixedly installed on one side of the quick-change welding bracket 2 8. The zero-point locator male head 10 mates with the zero-point locator female head 6 of the quick-change disc assembly 1 to achieve precise positioning of the high-torque tightening assembly 2 and the quick-change disc assembly 1. The tightening assembly quick-change disc female head 9 mates with the tightening assembly quick-change disc male head 7 of the quick-change disc assembly 1 to achieve connection and quick-change of the high-torque tightening assembly 2 and the quick-change disc assembly 1. The inner rotor shaft nut fixture 12 is fixedly installed below the hollow reducer mounting base 13. The entire high-torque tightening assembly 2 uses the hollow reducer mounting base 13 as its structural foundation. The servo motor 15 provides tightening power, the hollow reducer 11 increases the output torque, and the high-torque dynamic torque sensor 14 detects the tightening torque in real time and feeds the signal back to the control system. Together with the servo motor 15, it forms a high-precision torque closed-loop control to ensure the accuracy of the tightening torque.

[0023] like Figure 4As shown, the flexible inner rotor shaft assembly 3 is mounted on the hollow reducer mounting base 13 together with the hollow reducer 11 through the hollow part of the hollow reducer 11. The flexible inner rotor shaft assembly 3 passes through the hollow reducer 11 of the high-torque tightening assembly 2, so that the inner rotor shaft anti-rotation fixture 22 and the inner rotor shaft nut fixture 12 can be aligned synchronously. This ensures a high degree of concentricity between the flexible inner rotor shaft assembly 3 and the high-torque tightening assembly 2. In actual operation, during tightening, only the central inner rotor shaft anti-rotation fixture 22 needs to be aligned, and the outer inner rotor shaft nut fixture 12 will be aligned accordingly, simplifying the operation steps. Specifically, the flexible inner rotor shaft assembly 3 includes an assembly fixing shaft 16, a shaft end cover 17, an assembly upper plate 18, a connecting shaft 19, a guide sleeve 20, a spring 21, and an inner rotor shaft anti-rotation fixture 22. The upper end of the fixed shaft 16 is fixedly mounted on the hollow reducer mounting base 13, coaxial with the hollow reducer 11. The lower end of the fixed shaft 16 is fixedly connected to the inner rotor shaft anti-rotation fixture 22. The lower end of the inner rotor shaft anti-rotation fixture 22 has an involute spline, and the inner rotor shaft is connected to the inner rotor shaft via the spline. During connection, the inner rotor shaft needs to rotate a small angle to fit the inner rotor shaft anti-rotation fixture 22. After proper installation, the spline can withstand large torque without the need for additional clamping support equipment. To accommodate the vertical displacement generated when the nut is tightened, the flexible component 3 of the inner rotor shaft incorporates a flexible section. Specifically, the upper plate 18 is coaxially mounted on the fixed shaft 16 and above the inner rotor shaft anti-rotation fixture 22. The upper plate 18 and the anti-rotation fixture 22 are connected by four connecting shafts 19. The upper end of each connecting shaft 19 is limited by a shaft end cap 17, and the lower end has a precision hole for fixing to the anti-rotation fixture 22. Four springs 21 are respectively fitted onto the four connecting shafts 19. Each spring 21 has a guide sleeve 20 at its upper end, which is fitted onto the connecting shaft 19 and fixedly connected to the upper plate 18, providing circumferential guidance for the connecting shaft 19. During rotation, as the nut is tightened, its height changes. The springs 21 in the flexible component 3 absorb this displacement, ensuring good contact between the spline of the inner rotor shaft nut fixture 12 and the nut's locking jaws. Meanwhile, the elastic force of spring 21 can ensure that the anti-rotation fixture 22 of the inner rotor shaft and the spline of the inner rotor shaft always have a good connection and will not come off accidentally.

[0024] The torque for tightening the nut is transmitted to the mounting base 13 through the hollow reducer 11, while the reaction torque is also transmitted to the same mounting base 13 through the flexible component 3 of the inner rotor shaft. The two torques form a couple inside the mounting base and cancel each other out, greatly reducing the requirements for the strength and stiffness of the external support structure.

[0025] This invention serves as a tooling solution for use in production lines where other actuators (such as gantry cranes, robots, etc.) are required. This tooling solution is installed onto the actuator via a quick-change plate assembly 1. Zero-point positioning and quick-change connection of the high-torque tightening assembly 2 are achieved through the zero-point positioner female head 6 and the zero-point positioner male head 10. Power supply, air supply and communication functions are provided through the tooling docking with the quick-change plate 4 and the tightening assembly quick-change plate male head 7.

[0026] like Figure 5 As shown, after the entire fixture is installed in place, the locking nut is first manually inserted and rotated several times to establish a preliminary connection between the locking nut and the inner rotor shaft. Then, the flexible component 3 of the inner rotor shaft is manually placed onto the inner rotor shaft to mate with the spline position. Because the involute spline of the inner rotor shaft anti-rotation fixture 22 has a small module and a large number of teeth, only a relatively small rotation angle is needed to mate the spline shaft with the spline sleeve during docking. After the rotor shaft and fixture are properly mated, the angle between the fixture and the nut is further adjusted so that the inner rotor shaft nut fixture 12 can be precisely engaged in the notch of the locking nut.

[0027] After installation, the servo motor 15 can be started. The power output of the servo motor 15 is transmitted to the inner rotor shaft nut fixture 12 via the high-torque dynamic torque sensor 14, ultimately tightening the nut. During this process, the torque output by the servo motor 15 is further fed back by the high-torque dynamic torque sensor 14 to achieve closed-loop control and thus achieve high precision.

[0028] During rotation, as the nut is tightened, its height changes. The spring 21 in the inner rotor shaft flexible assembly 3 absorbs this displacement, ensuring good contact between the shaft spline and the nut's locking jaws. Furthermore, the locking torque is transmitted to the hollow reducer mounting base 13 via the hollow reducer 11, while the reaction torque on the rotor shaft spline is transmitted to the hollow reducer mounting base 13 via the fixed shaft 16 and connecting shaft 19. This design allows the tightening torque and reaction torque to cancel each other out within the mounting base, without affecting the external structure.

[0029] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A high-torque tightening fixture for a helicopter internal rotor shaft nut, characterized in that, The fixture includes a quick-change disc assembly (1), a high-torque tightening assembly (2), and an inner rotor shaft flexible assembly (3). The quick-change disc assembly (1) is used to suspend and connect the entire fixture to external equipment. The quick-change disc assembly (1) and the high-torque tightening assembly (2) are connected by a zero-point locator. The high-torque tightening assembly (2) and the inner rotor shaft flexible assembly (3) are both fixed on the hollow reducer mounting base (13) of the high-torque tightening assembly (2) and share the same axis. The tightening torque of the high-torque tightening assembly (2) is opposite to that of the inner rotor shaft flexible assembly (3). The torques are transmitted together to the hollow reducer mounting base (13) and cancel each other out; the high torque tightening assembly (2) includes a quick-change welding bracket two (8), a tightening assembly quick-change disc female head (9), a zero-point locator male head (10), a hollow reducer (11), an inner rotor shaft nut fixture (12), a hollow reducer mounting base (13), a high torque dynamic torque sensor (14), and a servo motor (15). The hollow reducer (11) is mounted on the hollow reducer mounting base (13), and the inner rotor shaft nut is installed at the output end of the hollow reducer (11). The tooling (12) is connected to the nut via a spline. The nut is tightened by rotating the hollow reducer (11). The output of the servo motor (15) is connected to the input end of the hollow reducer (11) via a high-torque dynamic torque sensor (14). The quick-change welding frame two (8) is fixedly installed above the hollow reducer mounting base (13). The tightening assembly quick-change disc female head (9) and the zero-point locator male head (10) are fixedly installed on one side of the quick-change welding frame two (8). The zero-point locator male head (10) and the quick-change disc The zero-point locator female head (6) of component (1) is connected to achieve precise positioning of the high-torque tightening component (2) and the quick-change plate component (1). The fast-change plate female head (9) of the tightening component is connected to the fast-change plate male head (7) of the fast-change plate component (1) to achieve connection and quick change of the high-torque tightening component (2) and the quick-change plate component (1). The inner rotor shaft nut fixture (12) is fixedly installed below the hollow reducer mounting base (13). The zero-point locator male head (10) and the zero-point locator female head (6) of the quick-change plate component (1) are connected. The flexible assembly (3) of the inner rotor shaft is mounted on the hollow reducer mounting base (13) together with the hollow reducer (11) through the hollow part of the hollow reducer (11); The flexible component (3) of the inner rotor shaft includes a component fixed shaft (16) and an inner rotor shaft anti-rotation fixture (22). The upper end of the fixed shaft (16) is fixedly installed on the hollow reducer mounting base (13) and is coaxial with the hollow reducer (11). The lower end of the fixed shaft (16) is fixedly connected to the inner rotor shaft anti-rotation fixture (22). The lower end of the inner rotor shaft anti-rotation fixture (22) has an involute spline. The inner rotor shaft anti-rotation fixture (22) is connected to the inner rotor shaft through the spline. The flexible assembly (3) of the inner rotor shaft also includes a shaft end cap (17), an upper plate (18), a connecting shaft (19), a guide sleeve (20), and a spring (21). The upper plate (18) is coaxially sleeved on the fixed shaft (16) and above the inner rotor shaft anti-rotation fixture (22). The upper plate (18) and the inner rotor shaft anti-rotation fixture (22) are connected by multiple connecting shafts (19). The upper end of the connecting shaft (19) is limited by the shaft end cap (17), and the lower end has a precision hole for fixing to the inner rotor shaft anti-rotation fixture (22). Multiple springs (21) are respectively sleeved on multiple connecting shafts (19). The upper end of the spring (21) is provided with a guide sleeve (20). The guide sleeve (20) is sleeved on the connecting shaft (19) and fixedly connected to the upper plate (18), providing circumferential guidance for the connecting shaft (19).

2. The high-torque tightening fixture for the helicopter internal rotor shaft nut according to claim 1, characterized in that, The quick-change tray assembly (1) includes a tooling docking quick-change tray (4), a quick-change welding frame (5), a zero-point locator female head (6), and a tightening component quick-change tray male head (7). The tooling docking quick-change tray (4) is fixedly installed above the quick-change welding frame (5). The zero-point locator female head (6) and the tightening component quick-change tray male head (7) are fixed on one side of the quick-change welding frame (5). The tooling docking quick-change tray (4) is used to connect with an external robot or gantry actuator to meet the connection and quick-change requirements of high-torque tightening tooling. The zero-point locator female head (6) is connected to the zero-point locator male head (10) of the high-torque tightening assembly (2) to achieve precise positioning of the quick-change disc assembly (1) and the high-torque tightening assembly (2). The fast-change disc male head (7) of the tightening assembly realizes the connection and quick-change function with the high-torque tightening assembly (2). The tooling docking quick-change disc (4) and the fast-change disc male head (7) of the tightening assembly are integrated with electrical interface and air interface. The electrical interface provides power supply and communication for the components in the high-torque tightening assembly (2). The gas interface supplies gas to the zero-point positioner and meets the gas supply needs of subsequent expansion products.

3. The high-torque tightening fixture for the helicopter internal rotor shaft nut according to claim 1, characterized in that, The flexible component (3) of the inner rotor shaft passes through the hollow reducer (11) of the high torque tightening component (2), so that the anti-rotation fixture (22) of the inner rotor shaft and the nut fixture (12) of the inner rotor shaft can be aligned synchronously.

4. A method for tightening a nut on an internal rotor shaft of a helicopter, using the tooling as described in any one of claims 1-3, characterized in that, Includes the following steps: The tooling is installed to an external actuator via a quick-change tray assembly (1); Connect the anti-rotation fixture (22) of the inner rotor shaft of the flexible assembly (3) to the spline of the inner rotor shaft; Adjust the tooling angle so that the inner rotor shaft nut tooling (12) of the high torque tightening assembly (2) aligns with the nut's bayonet. Start the servo motor (15) and tighten the nut through closed-loop torque control; During the tightening process, the spring (21) of the flexible component (3) of the inner rotor shaft absorbs the axial displacement, and the tightening torque and the counter torque cancel each other out in the hollow reducer mounting base (13).

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