A torsionally stiff helicopter mast hub

Abstract

The utility model belongs to the technical field of helicopter accessories, specifically relates to a torsional rigidity helicopter hub mast, and the utility model provides a torsional rigidity helicopter hub mast, aims at solving the problem that the inner mast is easy to produce shaking and deformation in the prior art, a torsional rigidity helicopter hub mast, including main rotor shaft and the inner mast of rotation connection in the main rotor shaft, the main rotor shaft with the inner mast all are hollow structure, the lower end of the inner mast extends the main rotor shaft, and, the lower end of the inner mast is fixed on the helicopter through the rotation stopping subassembly, the wall thickness of the inner mast is not less than 1.5 millimeter, the wall thickness of thicker increases the structural strength of the inner mast, in the process of helicopter flight, the inner mast can bear various force actions, such as torsional force, tension, pressure, bending force etc., the wall thickness of thicker can better resist the action of these forces, makes the inner mast not easy to deform.

Description

Technical Field

[0001] This utility model belongs to the field of helicopter parts technology, specifically relating to a helicopter rotor hub mast with high torsional stiffness. Background Technology

[0002] Currently, with the continuous iteration and maturation of helicopter technology and the vigorous development of the low-altitude economy, helicopters have been widely used in many fields such as power line inspection, hoisting operations, emergency rescue, and reconnaissance detection.

[0003] As a highly flexible aerial platform, helicopters can expand their functionality simply by adding specialized equipment to meet specific operational needs. From the perspective of current technology, mainstream helicopter equipment installation schemes share several common characteristics: equipment is concentrated in the nose and fuselage areas below the main rotor, only accommodating a limited range of equipment; the installation locations are relatively fixed, making it difficult to adjust the installation orientation according to equipment type and operational scenario. While this scheme currently meets basic equipment installation requirements, it suffers from limitations due to the installation area, resulting in obstructed equipment visibility, limited operational coverage, and insufficient compatibility with multiple devices simultaneously. It cannot fully adapt to operational scenarios requiring a wide-open high-altitude view, omnidirectional detection, or specific operational angles.

[0004] Optical equipment mounted on the nose is susceptible to interference from the fuselage structure and rotor airflow, resulting in blind spots. Equipment mounted on the belly is obstructed by ground obstacles or the fuselage itself, preventing omnidirectional observation and data acquisition. Furthermore, obstructions in the nose and belly areas can cause electromagnetic interference to communication equipment such as satellite communications and radar, leading to unstable signal transmission and reduced detection accuracy, particularly impacting long-distance communication and target detection in complex environments. The nose mounting position, limited by its fixed spatial layout and detection angle, not only fails to achieve 360° omnidirectional scanning but is also prone to signal obstruction from satellite communications and radar due to fuselage structure, significantly reducing the overall adaptability and efficiency of this mounting position. The operating radius of belly equipment is constrained by both fuselage height and rigging length, resulting in insufficient flexibility for operation in confined spaces such as canyons and urban complexes, making it difficult to meet the demands of efficient operation in complex scenarios. Limited installation space in the nose and belly can lead to equipment interference and insufficient mounting space when multiple devices (such as inspection sensors, communication relay equipment, and life detectors) need to be mounted simultaneously, hindering collaborative operation capabilities. Installing equipment on the nose can easily cause the fuselage's center of gravity to shift, especially when carrying heavy equipment, which can cause the center of gravity to tilt forward, affecting the helicopter's flight stability and maneuverability. In low-altitude, low-speed operations or complex airflow environments, additional power is required to maintain balance, increasing fuel consumption and flight risks.

[0005] Therefore, how to meet the installation and use requirements of special airborne equipment without affecting the flight performance of the helicopter is a technical problem that needs to be solved by those skilled in the art. For example, how to install airborne equipment such as satellite communication systems above the rotor.

[0006] In existing technology, equipment is installed above the rotor by setting an inner mast inside the main rotor shaft. This means the inner mast is stationary relative to the main rotation axis, and a mounting bracket for the equipment is located at its upper end. While this mast structure allows for equipment installation above the rotor, the inner mast structure is flawed and prone to vibration and deformation during practical use. Utility Model Content

[0007] This invention provides a helicopter rotor hub mast with anti-torsional stiffness, aiming to solve the problem of easy vibration and deformation of the inner mast in the prior art.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0009] A helicopter rotor hub mast with torsional stiffness includes a main rotor shaft and an inner mast rotatably connected to the main rotor shaft;

[0010] Both the main rotor shaft and the inner mast are hollow structures. The lower end of the inner mast extends out of the main rotor shaft, and the lower end of the inner mast is fixed to the helicopter by an anti-rotation assembly.

[0011] The wall thickness of the inner mast is not less than 1.5 mm.

[0012] A further improvement: the inner mast is made of No. 20 carbon steel.

[0013] Based on the above technical solution: No. 20 carbon steel has suitable strength, hardness and toughness. The inner mast made of it can better withstand various mechanical forces during helicopter flight, reduce the possibility of deformation, breakage and other failures of the inner mast, and thus improve the structural reliability of the helicopter mast device.

[0014] A further improved solution: the inner mast has a wall thickness of 3 mm.

[0015] Based on the above technical solution, a wall thickness of 3 mm significantly improves the structural strength of the inner mast. When helicopters perform high-intensity missions, such as high-speed flight, sharp turns, and rapid ascents and descents, the inner mast needs to withstand greater mechanical loads. A 3 mm wall thickness can better resist these loads, reducing the probability of damage such as breakage or deformation of the inner mast, thereby ensuring the normal operation of the helicopter mast assembly and improving the safety of helicopter flight.

[0016] A further improved design: the outer diameter of the inner mast is 34 mm to 48 mm.

[0017] Based on the above technical solution, an outer diameter of 34 mm to 48 mm ensures sufficient strength and rigidity for the inner mast while controlling its weight. An excessively heavy inner mast would increase the overall weight of the helicopter, leading to problems such as increased takeoff weight, reduced flight speed, and increased fuel consumption. This outer diameter strikes a balance between weight and strength, meeting the strength and rigidity requirements of the inner mast during helicopter flight without significantly negatively impacting the overall performance of the helicopter.

[0018] A further improved solution: The anti-rotation assembly includes an anti-rotation female seat, which tightens the inner mast into the slot by locking the slot with screws.

[0019] Based on the above technical solution: fixing the anti-rotation mount to the inner mast with screws effectively prevents the inner mast from rotating within the main rotor shaft. During helicopter flight, the presence of the anti-rotation assembly ensures that the inner mast remains in the correct position, improving the overall stability of the helicopter mast assembly.

[0020] A further improved solution: The anti-rotation female seat is provided with a slot, the cross-sectional shape of the slot is polygonal, and the lower end of the inner mast is inserted into the slot.

[0021] Based on the above technical solution, the insertion method of the polygonal slot into the lower end of the inner mast greatly enhances the anti-rotation capability. Compared with other simple anti-rotation methods, such as keyway anti-rotation, the polygonal slot can provide more comprehensive restraint, ensuring that the inner mast always remains in a stable position and improving the reliability of the helicopter mast assembly.

[0022] A further improvement: The screw is an internal hexagon head screw.

[0023] Based on the above technical solution: Hex socket head cap screws are operated using an Allen wrench, which can easily reach into confined spaces to tighten or loosen the screws. In helicopter mast systems, due to limited space, some ordinary screws may not be easily installed and removed, while hex socket head cap screws effectively solve this problem.

[0024] A further improved solution: The inner mast is rotatably connected to the main rotor shaft via an equipment adapter plate, and the equipment adapter plate is rotatably connected to the main rotor shaft.

[0025] Based on the above technical solution, the rotating connection achieved through bearings significantly reduces friction between the inner mast and the main rotor shaft. Friction is one of the main causes of wear on mechanical components; reducing friction can slow down the wear rate of components and extend their service life.

[0026] A further improved solution: The inner mast is fixedly connected to the equipment adapter plate by headless solid rivets.

[0027] Based on the above technical solution: headless solid rivet connection is a permanent connection method. Once riveted, the inner mast and equipment adapter plate are tightly joined together and difficult to separate. During helicopter flight, it is subjected to various complex aerodynamic and mechanical forces. This robust connection ensures that the inner mast and equipment adapter plate will not loosen or separate, guaranteeing the normal operation of the rotor system.

[0028] A further improved solution: The equipment adapter plate is equipped with an equipment mounting frame, which is a double-layer frame with an upper frame and a lower frame, and the upper frame and the lower frame are connected by a connecting pipe.

[0029] Based on the above technical solution: the double-layer design of the equipment mounting rack makes it versatile and adjustable. Its upper structure can be adjusted according to the different mounting holes of the installed equipment, while only the connection between the lower layer and the equipment adapter plate at the top of the mast remains unchanged.

[0030] The beneficial effects of this utility model are as follows:

[0031] The inner mast has a hollow structure, which reduces the overall weight of the structure. At the same time, the cables of the equipment and devices at the top of the mast can be routed through the mast tube to the belly of the machine, which facilitates wiring, simplifies the equipment integration process, and improves operational reliability.

[0032] The lower end of the inner mast is fixed to the helicopter via an anti-rotation assembly, which provides a stable support point for the inner mast. During helicopter flight, various forces on the inner mast (such as aerodynamic forces and forces transmitted by the main rotor shaft) are effectively constrained through this fixed point, reducing vibrations caused by uneven stress on the inner mast.

[0033] The inner mast has a wall thickness of no less than 1.5 mm, which increases its structural strength. During helicopter flight, the inner mast is subjected to various forces, such as torsional, tensile, compressive, and bending forces. A thicker wall better resists these forces, making the inner mast less prone to deformation. Attached Figure Description

[0034] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For users of ordinary skills in the art, other related drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is an exploded view of a helicopter rotor hub mast with torsional stiffness according to this utility model.

[0036] Figure 2 This is a schematic diagram of the internal structure of a helicopter rotor hub mast with torsional stiffness according to this utility model.

[0037] Figure 3 This is a schematic diagram of the connection between the stop servo and the main rotating shaft of a helicopter rotor hub mast with anti-torsional stiffness according to this utility model.

[0038] Explanation of the labels in the diagram:

[0039] 1-Equipment adapter plate; 2-Mast top bearing seat; 3-Upper bearing; 4-Lower bearing; 5-Mast locking threaded sleeve; 6-Mast top bearing washer; 7-Locking nut; 8-Headless solid rivet; 9-Inner mast; 10-Anti-rotation female seat; 11-Hex socket head cap screw; 12-Equipment mounting bracket; 13-Hex socket head cap screw; 14-Main rotor shaft. Detailed Implementation

[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model. All other embodiments obtained by users of the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0041] refer to Figures 1 to 3 A helicopter rotor hub mast with torsional stiffness includes a main rotor shaft and an inner mast rotatably connected to the main rotor shaft;

[0042] Both the main rotor shaft and the inner mast are hollow structures. The lower end of the inner mast extends out of the main rotor shaft, and the lower end of the inner mast is fixed to the helicopter by an anti-rotation assembly.

[0043] The wall thickness of the inner mast is not less than 1.5 mm.

[0044] Specifically: The inner mast is made of No. 20 carbon steel. The wall thickness of the inner mast is 3 mm. The outer diameter of the inner mast is 34 mm to 48 mm. The anti-rotation assembly includes an anti-rotation female seat, which tightens the inner mast into a slot by screws. The anti-rotation female seat has a clamp-like structure. A slot with a polygonal cross-section is provided on the anti-rotation female seat, and the lower end of the inner mast is inserted into the slot. The screws are hexagonal head screws. The inner mast is rotatably connected to the main rotor shaft via an equipment adapter plate, which is rotatably connected to the main rotor shaft. The inner mast is fixedly connected to the equipment adapter plate by headless solid rivets. The equipment adapter plate is equipped with an equipment mounting frame, which is a double-layered frame with an upper frame and a lower frame, connected by a connecting pipe.

[0045] The inner mast 9 is made of metal tubing, and its material, outer diameter, and wall thickness are important influencing factors, each having a different impact on the same equipment. The table below shows the impact of different materials, outer diameters, and wall thicknesses of the inner mast 9 on the same equipment during actual operation:

[0046]

[0047] The inner mast and main rotor shaft can be connected as follows: the inner mast 9 is rotatably connected to the main rotor shaft 14, and an equipment adapter plate 1 is fixed to the upper end of the inner mast 9; the equipment adapter plate 1 is mounted on the main rotor shaft 14 via a locking nut 7, the locking nut 7 including a lower threaded cylinder, which is fixed to the main rotor shaft 14 by threads, and an upper threaded cylinder, which is fixed to the lower threaded cylinder; a rolling bearing is provided between the equipment adapter plate and the upper threaded cylinder; the inner mast 9 is rotatably connected to the main rotor shaft 14 via the equipment adapter plate 1; the lower end of the inner mast 9 is fixedly connected to the helicopter fuselage. The inner mast 9 can be a hollow tube, which can reduce the overall structural weight, and at the same time, the cables of the equipment and devices at the top of the mast can be routed through the mast tube to the fuselage, facilitating wiring, simplifying the equipment integration process, and improving operational reliability. The equipment adapter plate 1 is riveted to the inner mast 9. The rivet is a headless solid rivet 8.

[0048] The rolling bearing includes an upper bearing 3 and a lower bearing 4, which are coaxially arranged. Both the upper bearing 3 and the lower bearing 4 are deep groove ball bearings. A mast locking threaded sleeve 5 for positioning the inner ring of the rolling bearing is also provided inside the upper threaded cylinder. A mast top bearing washer 6 for positioning the outer ring of the rolling bearing is also provided inside the upper threaded cylinder. A mast top bearing seat is also provided inside the upper threaded cylinder, and the rolling bearing is disposed within the mast top bearing seat. The upper threaded cylinder and the lower threaded cylinder are an integral structure.

[0049] The equipment adapter plate 1 is provided with an equipment mounting bracket 12, and the equipment adapter plate 1 is provided with multiple equipment assembly holes. The equipment mounting bracket 12 is fixed to the equipment adapter plate 1 by hex socket screws 13. The equipment mounting bracket 12 is a double-layered frame with an upper frame and a lower frame, and the upper frame and the lower frame are connected by a connecting pipe.

[0050] This utility model provides a helicopter rotor hub mast with anti-torsional stiffness, possessing dynamic stability and a wide field of vision. It can keep the equipment mounted on the top of the rotor shaft relatively stationary from the fuselage when the main rotor shaft 14 rotates at high speed, and the top installation has an unobstructed field of vision. It provides a stable mounting foundation for various equipment and devices while improving the detection range and accuracy of the equipment. The deep groove ball bearing design provides diverse load-bearing capacity, capable of withstanding the tensile force of the entire aircraft's lifting weight as well as the pressure of equipment such as radar and satellite communication antennas, expanding the operating range and equipment compatibility. The inner mast 9 is made of No. 20 carbon steel, with an outer diameter of 34mm to 48mm and a wall thickness of ≥3mm. These figures were obtained through testing and selection, meeting the requirements of the loaded equipment while maintaining a certain degree of miniaturization and lightweight. The equipment adapter plate 1 adopts a multi-hole design, possessing excellent load-bearing capacity while allowing for multiple installation and fixing schemes.

[0051] The double-layer design of the equipment mounting bracket 12 makes it versatile and adjustable. Its upper structure can be adjusted according to the different mounting holes of the installed equipment, as long as the connection between the lower layer and the equipment adapter plate 1 remains unchanged. The mounting holes are coaxial with the main rotor shaft 14, avoiding the risk of center of gravity shift and balancing flight safety and functional expansion. The overall structure is simple, compact, and lightweight, saving manufacturing and modification costs without affecting the overall aircraft layout. The high-mounted top mounting enables 360° omnidirectional detection, breaking through the limitations of fuselage height and cabin space, increasing the flexibility of operation in narrow spaces, and significantly expanding the operational coverage area.

[0052] The working principle of this embodiment:

[0053] Installation method: First, fit the top bearing housing of the mast into the equipment adapter plate 1. Then, place the upper deep groove ball bearing and the lower deep groove ball bearing into the gap between the equipment adapter plate 1 and the top bearing housing of the mast. Next, use the mast locking threaded sleeve 5 to lock and fix the inner rings of the two bearings. Then, first, place the top bearing washer 6 of the mast into the main rotor fixing locking nut 7, and then lock the main rotor fixing locking nut 7 to the top bearing housing of the mast. At this time, the top bearing washer 6 of the mast can fix the outer rings of the two bearings. Use headless solid rivets 8 to rivet the equipment adapter plate 1 to the inner mast 9. Finally, fix the inner mast 9 directly or through other structures to the helicopter fuselage or fuselage accessories. For example, the lower end of the inner mast 9 can be fixed to the helicopter accessories through the anti-rotation nut 10 and the hex socket head cap screw 11, etc.

[0054] Working principle: There is no direct contact between the main rotor shaft 14 and the inner mast 9. The two bearings enable the inner mast 9 to be fixed inside the main rotor shaft 14 but not to rotate with the main rotor shaft 14. This allows the equipment installed on the equipment mounting frame 12 to remain stationary with the main rotor shaft 14. The equipment and the helicopter as a whole remain relatively stationary. In addition, the inner mast 9 has a hollow structure, which allows the equipment cables of the equipment on the equipment mounting frame 12 to be routed to the fuselage for convenient power supply and control, thus improving the versatility of the mast. Furthermore, the equipment mounting frame 12 has a double-layer structure. The upper layer can be adjusted according to the different mounting holes of the installed equipment, while only the connection between the lower layer and the equipment adapter plate 1 needs to remain unchanged.

[0055] This utility model is not limited to the above-mentioned optional embodiments. Under the premise of non-contradiction, the various solutions can be combined arbitrarily. Anyone can derive other forms of products under the guidance of this utility model. However, no matter what changes are made in their shape or structure, all technical solutions that fall within the scope of the claims of this utility model are within the protection scope of this utility model.

Claims

1. A torsionally stiff helicopter mast hub pole, characterized by: Includes a main rotor shaft and an inner mast rotatably connected to the main rotor shaft; Both the main rotor shaft and the inner mast are hollow structures. The lower end of the inner mast extends out of the main rotor shaft, and the lower end of the inner mast is fixed to the helicopter by an anti-rotation assembly. The wall thickness of the inner mast is not less than 1.5 mm.

2. A torsional stiffness helicopter mast hub post according to claim 1, characterised in that: The inner mast is made of No. 20 carbon steel.

3. A helicopter rotor hub mast with anti-torsional stiffness according to claim 2, characterized in that: The inner mast has a wall thickness of 3 mm.

4. A helicopter rotor hub mast with anti-torsional stiffness according to claim 2 or 3, characterized in that: The outer diameter of the inner mast is 34 mm to 48 mm.

5. A helicopter rotor hub mast with anti-torsional stiffness according to claim 1, characterized in that: The anti-rotation assembly includes an anti-rotation female seat, which tightens the inner mast into the slot by locking the slot with screws.

6. A torsional stiffness helicopter mast hub post according to claim 5, characterised in that: The anti-rotation female seat is provided with a slot, the cross-sectional shape of which is polygonal, and the lower end of the inner mast is inserted into the slot.

7. A torsional stiffness helicopter mast hub post according to claim 6, characterised in that: The screw is an internal hexagon head screw.

8. A torsional stiffness helicopter mast hub post according to claim 1, characterized in that: The inner mast is rotatably connected to the main rotor shaft via an equipment adapter plate, and the equipment adapter plate is rotatably connected to the main rotor shaft.

9. A torsional stiffness helicopter mast hub post according to claim 8, characterised in that: The inner mast is fixedly connected to the equipment adapter plate by headless solid rivets.

10. A helicopter rotor hub mast with anti-torsional stiffness according to claim 9, characterized in that: The equipment adapter plate is equipped with an equipment mounting frame, which is a double-layer frame with an upper frame and a lower frame. The upper frame and the lower frame are connected by a connecting pipe.

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