Hingeless hub and helicopter

Abstract

This invention discloses a hingeless rotor hub and a helicopter, belonging to the field of helicopter technology. It solves the problems of existing hingeless rotor hubs, which use complex metal bearing hooks, have high requirements for sealing, assembly, lubrication, precision, and working environment, and suffer from wear, indentation, and gaps after prolonged operation. The hingeless rotor hub includes a flexible bearing and a central hub component. The central hub component is located on the outer wall of the flexible bearing, and the helicopter's rotor clamp is located on the inner wall of the flexible bearing. The flexible bearing comprises, from the outside to the inside, an outer connecting layer, a stacked layer, and an inner connecting layer, sequentially nested together. The outer connecting layer is fixedly connected to the central hub component; the inner connecting layer is fixedly connected to the rotor clamp; the stacked layer includes radially alternating elastic and rigid layers. This hingeless rotor hub can be used to connect the rotor hub and rotor clamp.

Description

Technical Field

[0001] This invention belongs to the field of helicopter technology, and particularly relates to a hingeless rotor hub and a helicopter. Background Technology

[0002] Hingeless or bearingless rotors offer high control efficiency, enhancing the helicopter's maneuverability and responsiveness. Therefore, many aircraft, both domestically and internationally, are designed with hingeless rotors (BO105 or Lynx) or bearingless rotors (EC135).

[0003] Currently, existing hingeless rotor hubs for helicopters mainly take the following form: they are achieved using metal bearings and tension bars, but they have the following shortcomings:

[0004] On the one hand, the existing hingeless propeller hub structure is complex, and the metal bearing requires a large number of parts for positioning, sealing and lubrication to ensure that the bearing working environment meets the usage requirements; on the other hand, the metal bearing requires high precision parts and precise fit, which leads to high machining costs and high scrap rate.

[0005] On the other hand, existing hingeless propeller hubs use metal bearings, which have high requirements for the working environment and cannot work in harsh environments such as rain, dust, and salt spray. They require a lot of sealing design to maintain a clean working environment for the bearings.

[0006] On the other hand, the rotor hub operates under high load and high frequency cyclic oscillation motion. Metal bearings will experience wear, indentation, and clearance problems when working under such conditions for a long time, resulting in a short lifespan overall. Summary of the Invention

[0007] Based on the above analysis, the present invention aims to provide a hingeless rotor hub and helicopter, which solves the problems of the prior art where hingeless rotor hubs use complex metal bearing hooks, have high requirements for sealing, assembly, lubrication, precision and working environment, and will develop wear, indentation and gaps after long-term operation.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] The present invention provides a hingeless rotor hub, including an elastic bearing and a rotor hub central component; the rotor hub central component is disposed on the outer wall of the elastic bearing, and the helicopter rotor clamp is disposed on the inner wall of the elastic bearing; the elastic bearing includes an outer connecting layer, a stacked layer and an inner connecting layer sequentially sleeved from the outside to the inside; the outer connecting layer is fixedly connected to the rotor hub central component; the inner connecting layer is fixedly connected to the rotor clamp; the stacked layer includes an elastic layer and a rigid layer alternately sleeved in the radial direction.

[0010] Furthermore, there are two elastic bearings, and the central component of the propeller hub is connected to the propeller clamp through the two elastic bearings.

[0011] Furthermore, both the inner and outer end faces of the laminate are elastic layers.

[0012] Furthermore, the elastic bearing is cylindrical in shape.

[0013] Furthermore, the outer connecting layer includes a connecting cylinder and a connecting ring located at one end of the connecting cylinder and fixedly connected to the connecting cylinder; the outer wall of the connecting cylinder and the side wall of the connecting ring are both fixedly connected to the central component of the propeller hub.

[0014] Furthermore, the connecting cylinder and the connecting ring are integrally formed.

[0015] Furthermore, it also includes a torsion bar, one end of which is fixedly connected to the central component of the propeller hub, and the other end of which is fixedly connected to the propeller clamp.

[0016] The present invention also provides a helicopter, including a rotor blade, a rotor clamp for holding the rotor blade, and the aforementioned hingeless rotor hub.

[0017] Furthermore, the blades are fixedly connected to the blade clamps via main blade counterweight bolts.

[0018] Furthermore, the helicopter is defined as one weighing less than 500 kg.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] a) The hingeless propeller hub provided by this invention, while ensuring the same design and functional requirements, uses elastic bearings to replace the metal bearings of the original propeller hub, which can greatly simplify the structure of the hingeless propeller hub, effectively reduce the types and number of parts, eliminate the need for special sealing structures, reduce the machining precision of parts, and the life of elastic bearings is much longer than that of metal bearings. It can effectively solve the problems of complex hooks, high requirements for sealing, assembly, lubrication, precision and working environment, and wear, indentation and gaps that occur after long-term operation when using metal bearings in hingeless propeller hubs.

[0021] (b) The hingeless propeller hub provided by this invention employs an elastic laminate, capable of withstanding sufficient flapping and oscillating lift forces. This allows the laminate to exhibit sufficient elastic deformation, reducing the machining precision required and improving its sealing performance. Furthermore, the sealing performance of the elastic layer is typically greater than that of the rigid layer, and the elastically deformable laminate itself possesses a certain degree of sealing. Therefore, excessive sealing design is unnecessary, effectively reducing the number of parts in the elastic bearing and improving its environmental adaptability. In addition, since the weight of the elastic layer is generally less than that of the rigid layer, the inclusion of the elastic layer effectively reduces the overall weight of the elastic bearing.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0023] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0024] Figure 1 This is a schematic diagram of the hingeless rotor hub provided in Embodiment 1 of the present invention. In order to better understand the connection relationship between the rotor hub and the rotor clip of the helicopter, the rotor clip of the helicopter is also shown in this figure.

[0025] Figure 2 This is a partial view of the connection relationship between the hingeless rotor hub and the helicopter rotor clip provided in Embodiment 1 of the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the elastic bearing in the hingeless propeller hub provided in Embodiment 1 of the present invention;

[0027] Figure 4 This is a cross-sectional view of the elastic bearing in the hingeless propeller hub provided in Embodiment 1 of the present invention.

[0028] Figure 5 This is a schematic diagram of the main rotor counterweight bolt in a helicopter provided in Embodiment 2 of the present invention.

[0029] Figure label:

[0030] 1-Blade; 2-Blade clamp; 3-Main blade bolt; 4-Dynamic balance weight; 5-Pressure nut; 6-Cotter pin; 7-Screw; 8-Blade hub center component; 9-Elastic bearing; 91-Internal spline; 92-Elastic layer; 93-Rigid layer; 94-Connecting cylinder; 95-Connecting ring; 96-External spline; 97-Inner connecting layer; 10-Torsion bar. Detailed Implementation

[0031] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0032] Example 1

[0033] This embodiment provides a hingeless propeller hub; see [link / reference] Figures 1 to 4It includes a flexible bearing 9 and a rotor hub central component 8. The rotor hub central component 8 is connected to the helicopter rotor clip 2 through the flexible bearing 9. That is, from the inside to the outside, the rotor clip 2, the flexible bearing 9 and the rotor hub central component 8 are sequentially fitted together. The rotor hub central component 8 is located on the outer wall of the flexible bearing 9 and the rotor clip 2 is located on the inner wall of the flexible bearing 9.

[0034] Specifically, the structure of the elastic bearing 9 is a cylindrical elastic bearing with a stacked structure, which includes an outer connecting layer, a stack, and an inner connecting layer 97 that are sequentially stacked from the outside to the inside. The outer connecting layer is fixedly connected to the central part 8 of the propeller hub, and the inner connecting layer 97 is fixedly connected to the propeller clamp 2. The stack includes an elastic layer 92 (e.g., a rubber layer) and a rigid layer 93 (e.g., a metal layer) that are alternately stacked in the radial direction.

[0035] Compared with the prior art, the hingeless propeller hub provided in this embodiment, while ensuring the same design and functional requirements, uses an elastic bearing 9 to replace the metal bearing of the original hingeless propeller hub. This can greatly simplify the structure of the hingeless propeller hub, effectively reduce the types and number of parts, eliminate the need for special sealing structures, reduce the machining precision of parts, and the life of the elastic bearing 9 is much longer than that of the metal bearing. It can effectively solve the problems of complex hooks, high requirements for sealing, assembly, lubrication, precision and working environment, and wear, indentation and gaps that occur after long-term operation when using metal bearings in hingeless propeller hubs.

[0036] Specifically, the use of an elastic laminate allows it to withstand sufficient wagging and oscillating lift forces, enabling the laminate to have sufficient elastic deformation, reducing the machining precision required and improving its sealing performance. Simultaneously, the sealing performance of the elastic layer 92 is typically greater than that of the rigid layer 93, and the elastically deformable laminate itself possesses a certain degree of sealing. Therefore, excessive sealing design is unnecessary, effectively reducing the number of parts in the elastic bearing 9 and improving its environmental adaptability. Furthermore, since the weight of the elastic layer 92 is typically less than that of the rigid layer 93, the inclusion of the elastic layer 92 effectively reduces the overall weight of the elastic bearing 9.

[0037] For example, the elastic bearing 9 is cylindrical in shape, that is, the elastic bearing 9 is a cylindrical elastic bearing 9.

[0038] To ensure a stable connection between the propeller hub central component 8 and the propeller clamp 2, the number of the aforementioned elastic bearings 9 can be multiple, for example, two. The propeller hub central component 8 is connected to the propeller clamp 2 through two elastic bearings 9.

[0039] In practical applications, the laminated structure withstands the flapping force and oscillation lift generated by the blade 1 mainly through the relative circumferential rotation between the inner and outer walls of the elastic layer 92. However, it is worth noting that the relative circumferential rotation between the inner and outer walls of the elastic layer 92 causes the material of the elastic layer 92 to be subjected to shear forces. Thus, once the relative circumferential rotation between the inner and outer walls of the elastic layer 92 exceeds the maximum shear force that the material of the elastic layer 92 can withstand, the material of the elastic layer 92 will be damaged, leading to the overall failure of the elastic bearing 9. Therefore, it is necessary to appropriately limit the relative circumferential rotation between the inner and outer walls of the elastic layer 92 to avoid damaging the elastic layer 92. For example, a limiting spline assembly is provided between two rigid layers 93 adjacent to one of the elastic layers 92. The limiting spline assembly is used to limit the relative circumferential rotation between the inner and outer walls of the elastic layer 92.

[0040] Specifically, a first rigid layer 93 adjacent to the inner wall of the elastic layer 92 is defined as the first rigid layer, and a second rigid layer 93 adjacent to the outer wall of the elastic layer 92 is defined as the second rigid layer. The outer wall of the first rigid layer has multiple first spline protrusions along its circumference, with a first spline groove between two adjacent first spline protrusions. The inner wall of the second rigid layer has multiple second spline protrusions along its circumference, with a second spline groove between two adjacent second spline protrusions. The first spline protrusions are inserted into the second spline grooves, and the sidewalls of the first spline protrusions and the second spline grooves have a first gap; the second spline protrusions are inserted into the second spline grooves, and the sidewalls of the second spline protrusions and the first spline grooves have a second gap. It should be noted that the elastic layer 92 is not disposed in the first gap or the second gap. In this way, the first spline protrusion can only move in the second spline groove, and the second spline protrusion can only move in the first spline groove. That is to say, the relative circumferential rotation distance between the inner wall and the outer wall of the elastic layer 92 is the minimum value of the first gap and the second gap. This can appropriately limit the relative circumferential rotation between the inner wall and the outer wall of the elastic layer 92, and can basically prevent the elastic layer 92 from being damaged, thereby improving the safety of the aforementioned hingeless propeller hub.

[0041] To ensure a stable connection between the elastic bearing 9 and the central component 8 of the propeller hub, the outer connecting layer specifically includes a connecting cylinder 94 and a connecting ring 95 located at one end of the connecting cylinder 94 and fixedly connected to it. In practical applications, the connecting cylinder 94 and the connecting ring 95 can be integrally formed, with both the outer wall of the connecting cylinder 94 and the side wall of the connecting ring 95 fixedly connected to the central component 8 of the propeller hub. This dual connection, where both the connecting cylinder 94 and the connecting ring 95 are fixedly connected to the central component 8 of the propeller hub, ensures a stable connection between the elastic bearing 9 and the central component 8 of the propeller hub. Furthermore, it should be noted that the connecting ring 95 also restricts the axial movement of the elastic bearing 9, thereby bearing some of the centrifugal force generated by the propeller blade 1.

[0042] It should be noted that, in order to ensure that the elastic bearing 9 has sufficient mechanical strength, both the inner connecting layer 97 and the outer connecting layer are rigid components.

[0043] For example, the inner connecting layer 97 and the propeller clip 2, as well as the outer connecting layer and the propeller hub central member 8, can be detachably and fixedly connected by a spline structure. Specifically, the inner wall of the inner connecting layer 97 is provided with an inner spline 91 protrusion, which cooperates with the spline groove of the propeller clip 2 provided on the propeller clip 2; the outer wall of the outer connecting layer is provided with an outer spline 96 protrusion, which cooperates with the spline groove of the propeller hub central member 8 provided on the propeller hub central member 8.

[0044] It should be noted that, in order to facilitate the connection between the stack and the inner connecting layer 97 and the outer connecting layer, both the inner end face and the outer end face of the stack are elastic layers 92.

[0045] For example, the number of rigid layers 93 is 1 to 3, and the number of elastic layers 92 is 2 to 4. That is, if the number of rigid layers 93 is 1, then the number of elastic layers 92 is 2, and the stack includes elastic layers 92, rigid layers 93 and elastic layers 92 nested together in sequence; if the number of rigid layers 93 is 3, then the number of elastic layers 92 is 4, and the stack includes elastic layers 92, rigid layers 93, elastic layers 92, rigid layers 93, elastic layers 92, rigid layers 93 and elastic layers 92 nested together in sequence.

[0046] It is worth noting that in the elastic bearing 9, the elastic layer 92 is mainly used to bear the flapping force and oscillation lift generated by the blade 1, while the rigid layer 93 is mainly used to ensure the mechanical strength of the elastic bearing 9. The rigid layer 93 is only required to ensure mechanical strength. Therefore, the radial thickness of the rigid layer 93 is less than the radial thickness of the elastic layer 92.

[0047] To ensure that the elastic bearing 9 has sufficient mechanical properties, the radial thickness of the elastic bearing 9 is 8 to 40 mm, such as 8 mm, 16 mm, 25 mm, 36 mm or 40 mm.

[0048] In order to enable the outer wall of the elastic bearing 9 to be detachably and fixedly connected to the central component 8 of the propeller hub, for example, the outer wall of the elastic bearing 9 is provided with an external spline 96, and the inner wall of the central component 8 of the propeller hub is provided with a central spline. The external spline 96 and the central spline cooperate with each other to enable the outer wall of the elastic bearing 9 to be detachably and fixedly connected to the central component 8 of the propeller hub.

[0049] Similarly, in order to achieve a detachable and fixed connection between the inner wall of the elastic bearing 9 and the propeller clamp 2, for example, the inner wall of the elastic bearing 9 is provided with an inner spline 91, and the outer wall of the propeller clamp 2 is provided with a propeller clamp 2 spline. The inner spline 91 and the propeller clamp 2 spline cooperate with each other to achieve a detachable and fixed connection between the inner wall of the elastic bearing 9 and the propeller clamp 2.

[0050] Understandably, in order for the aforementioned hingeless propeller hub to withstand the centrifugal force generated by the propeller blade 1, it also includes a torsion bar 10. One end of the torsion bar 10 is fixedly connected to the central component 8 of the propeller hub, and the other end of the torsion bar 10 is fixedly connected to the propeller clamp 2. By setting the torsion bar 10, the axial movement between the propeller hub and the propeller clamp 2 can be limited, thereby enabling it to withstand the centrifugal force generated by the propeller blade 1.

[0051] Example 2

[0052] This embodiment provides a helicopter, including a rotor blade 1, a rotor clip 2 for holding the rotor blade 1, and a hingeless rotor hub provided in Embodiment 1.

[0053] Compared with the prior art, the beneficial effects of the helicopter provided in this embodiment are basically the same as those of the hingeless rotor hub provided in Embodiment 1, and will not be described in detail here.

[0054] For example, the blade 1 is fixedly connected to the blade clamp 2 by the main blade counterweight bolts. Specifically, see [link to relevant documentation]. Figure 5 The main rotor counterweight bolt includes a main rotor bolt 3, a dynamic balance counterweight block 4, and a screw 7. The screw 7 and the dynamic balance counterweight block 4 are located at the bolt head end of the main rotor bolt 3. One end of the screw 7 is fixedly connected to the bolt head, and the dynamic balance counterweight block 4 is sleeved on the screw 7 and detachably connected to the screw 7.

[0055] Compared with the prior art, the main rotor counterweight bolt of this embodiment is suitable for dynamic balance adjustment of small helicopters. It should be noted that small helicopters refer to helicopters weighing less than 500 kg. The dynamic balance counterweight 4 is set at the bolt head end of the main rotor bolt 3 by the screw 7. When the rotor blade 1 is disassembled, the dynamic balance counterweight 4 can always be disassembled and installed together with the main rotor bolt 3, so as to ensure that the dynamic balance counterweight 4 will not be lost during the disassembly process. When reinstalling the rotor blade 1, there is no need to reassemble the dynamic balance counterweight 4, which can greatly improve the maintenance efficiency of the helicopter.

[0056] Meanwhile, since the screw 7 is set separately for installing the dynamic balance counterweight 4, the number and quality of the dynamic balance counterweight 4 can be effectively increased, thereby improving the helicopter's dynamic balance adjustment capability.

[0057] Furthermore, the structure of the aforementioned main rotor counterweight bolt can be improved based on the existing main rotor bolt 3, namely, by fixing the screw 7 to the bolt head end of the main rotor bolt 3, which is convenient and simple to operate and adaptable to industrial production and application.

[0058] To reduce the impact of the installation of the screw 7 on the structure of the main rotor bolt 3, the length ratio of the main rotor bolt 3 to the screw 7 can be controlled within the range of 3.0 to 5.0 (e.g., 3.0, 3.3, 3.6, 4.2, 4.5 or 5.0). For example, when the main rotor bolt 3 is 90 mm, the length of the screw 7 can be 20 mm.

[0059] In this embodiment, the counterweight bolt of the main propeller has a counterweight range of 0 to 90g. For example, the counterweight of the dynamic balance counterweight 4 is 25g, 40g, 60g, 75g or 90g.

[0060] During helicopter flight or maintenance, to prevent the dynamic balance weight 4 from falling off, the main rotor counterweight bolt also includes a clamping nut 5. The clamping nut 5 is sleeved on the screw 7 and is detachably threaded to the screw 7. The clamping nut 5 is located at the end of the dynamic balance weight 4 away from the main rotor bolt 3. The clamping nut 5 can limit the axial movement of the dynamic balance weight 4, preventing it from coming off the screw 7.

[0061] In practical applications, after repeated use and vibration, the clamping nut 5 may loosen or fall off. Therefore, the aforementioned main rotor counterweight bolt also includes a cotter pin 6 located at the end of the screw 7 away from the main rotor bolt 3. The cotter pin 6 is detachably fixed to the screw 7. The cotter pin 6 is located on the side of the clamping nut 5 away from the main rotor bolt 3. It can be understood that the end of the screw 7 away from the main rotor bolt 3 has a through hole, and the cotter pin 6 is inserted into the through hole. In this way, through the double cooperation of the clamping nut 5 and the cotter pin 6, the dynamic balance counterweight 4 can be basically prevented from falling off, thereby ensuring the flight safety of the helicopter.

[0062] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A hingeless propeller hub, characterized in that, It includes a flexible bearing and a rotor hub central component; the rotor hub central component is located on the outer wall of the flexible bearing, and the helicopter rotor clamp is located on the inner wall of the flexible bearing. The elastic bearing comprises, from the outside to the inside, an outer connecting layer, a stacked layer, and an inner connecting layer that are sequentially sleeved together; the outer connecting layer is fixedly connected to the central component of the propeller hub; the inner connecting layer is fixedly connected to the propeller clamp; the stacked layer comprises an elastic layer and a rigid layer that are alternately sleeved together radially. The outer connecting layer includes a connecting cylinder and a connecting ring located at one end of the connecting cylinder and fixedly connected to the connecting cylinder; the outer wall of the connecting cylinder and the side wall of the connecting ring are both fixedly connected to the central component of the propeller hub, and the connecting ring bears part of the centrifugal force generated by the propeller blades. A limiting spline assembly is provided between two rigid layers adjacent to one of the elastic layers. The rigid layer adjacent to the inner wall of the elastic layer is the first rigid layer, and the rigid layer adjacent to the outer wall of the elastic layer is the second rigid layer. The outer wall of the first rigid layer has multiple first spline protrusions along the circumferential direction, and a first spline groove is formed between two adjacent first spline protrusions. The inner wall of the second rigid layer has multiple second spline protrusions along the circumferential direction, and a second spline groove is formed between two adjacent second spline protrusions. The first spline protrusions are inserted into the second spline grooves, and the sidewalls of the first spline protrusions and the second spline grooves have a first gap. The second spline protrusions are inserted into the second spline grooves, and the sidewalls of the second spline protrusions and the first spline grooves have a second gap. No elastic layer is provided in the first gap and the second gap.

2. The hingeless propeller hub according to claim 1, characterized in that, The number of elastic bearings is two, and the central component of the propeller hub is connected to the propeller clamp through the two elastic bearings.

3. The hingeless propeller hub according to claim 1, characterized in that, Both the inner and outer ends of the stacked layers are elastic layers.

4. The hingeless propeller hub according to claim 1, characterized in that, The elastic bearing is cylindrical in shape.

5. The hingeless propeller hub according to claim 1, characterized in that, The connecting cylinder and the connecting ring are integrally formed.

6. The hingeless propeller hub according to any one of claims 1 to 5, characterized in that, It also includes a torsion bar, one end of which is fixedly connected to the central component of the propeller hub, and the other end of which is fixedly connected to the propeller clamp.

7. A helicopter, characterized in that, It includes blades, blade clamps for holding the blades, and a hingeless blade hub as described in any one of claims 1 to 6.

8. The helicopter according to claim 7, characterized in that, The blades are fixedly connected to the blade clamps via main blade counterweight bolts.

9. The helicopter according to claim 8, characterized in that, The helicopter in question is a helicopter weighing less than 500 kg.

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