Multi-section blade capable of freely adjusting pitch
By adopting multi-stage blades with freely adjustable pitch in the helicopter rotor, the problems of automatic tilter complexity and vibration transmission are solved, achieving higher lift and lower vibration and noise.
Patent Information
- Application Number
- CN202510215792.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-05-13
AI Technical Summary
The complexity of automatic incliners in existing helicopter rotors and their impact on vibration transmission makes it difficult to increase lift without changing the aerodynamic shape of the blades.
A multi-stage blade that can freely adjust the pitch is used to adjust the pitch by adjusting the power of the adjustment unit on the rod. The blades are divided into the root section, the middle section and the tip section. Each section has an independent adjustment function to optimize the lift and vibration performance of the rotor.
It is achieved to increase the maximum lift of the rotor while keeping the blade aerodynamic shape unchanged, reduce vibration and noise, and simplify the structure, reduce mass and complexity.
Smart Images
Figure CN119975771A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of aircraft structure design, and in particular to a multi-section blade with freely adjustable pitch. Background Art
[0002] To reduce shock waves, helicopter rotor blades are often modified with special features (e.g., sweep and forward thrust). Furthermore, to adjust the blade pitch, a tiltrotor is often used to adjust the rotor's collective pitch and cyclic pitch. In today's helicopter rotors, the tiltrotor is essentially an integral feature of rotor design. However, the complexity of existing tiltrotor mechanisms and their impact on rotor vibration transmission are inherent issues.
[0003] In addition to using automatic tilt devices to adjust the pitch, everyone also hopes that the rotor can generate greater lift while keeping the aerodynamic shape of the blades unchanged.
[0004] To solve the above problems, the current solutions include: HHC blades, which adjust the blade angle through high-frequency harmonic control algorithms to reduce the vibration amplitude of the rotor; RBC blades, which adjust the blade angle by integrating a rotating mechanism directly at the blade root; AFC blades, which control boundary layer separation with pulsed jets by arranging an array of micro-jet holes on the surface to increase lift; and ATR blades, which can automatically adjust the tip twist angle to avoid and weaken tip shock waves and reduce vibration.
[0005] A multi-section blade with freely adjustable pitch uses a simpler method to adjust the blade pitch and can increase the maximum lift of the rotor, reduce vibration and noise. The blade is divided into three sections, and the pitch is adjusted by adjusting the power of the adjustment unit on the adjustment rod. Each of the three sections of the blade also has its own function. The root section reduces the pitch when entering the backflow area, reducing the downward force and resistance brought by this section; the middle section (main lift section) can increase the angle of attack of this section to increase lift because it can ignore the influence of backflow and stall at both ends; the tip section takes into account that an excessively large pitch in the stall area will cause shock waves, resulting in a sudden increase in resistance. The pitch is appropriately reduced to avoid and weaken the shock wave at the tip as much as possible and reduce the vibration caused by the shock wave. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a multi-section blade with freely adjustable pitch in view of the defects involved in the background technology.
[0007] The present invention adopts the following technical solutions to solve the above technical problems: A multi-segment propeller blade with freely adjustable pitch, comprising a fixed end, a root segment, a first flexible segment, a middle segment, a second flexible segment, a tip segment, a rigid rod, N bearings, and an adjustment module, where N is a natural number greater than or equal to 1; The fixed end, the blade root section, the first flexible section, the middle section, the second flexible section, and the blade tip section are connected in sequence; The rigid rod is disposed in the beam of the blade, with one end fixedly connected to the fixed end and the other end sequentially passing through the root section, the first flexible section, the middle section, the second flexible section, and then extending into the tip section; the rigid rod can bend in the flapping direction, but is extremely rigid in the torsion direction and is almost impossible to bend; The N bearings are equidistantly arranged on the rigid rod, the inner rings are coaxially fixedly connected to the rigid rod, and the outer rings are fixedly connected to the inner wall of the internal beam of the blade through the bearing seat; The regulating module includes M1+M2+M3 regulating units, where M1, M2, and M3 are all natural numbers greater than or equal to 1; the regulating unit includes an electromagnetic coil and an excitation coil; the excitation coil is sleeved outside the electromagnetic coil and is coaxial with the electromagnetic coil, and can rotate after being driven by the electromagnetic coil; Among the M1+M2+M3 adjustment units, the M1 adjustment units are equidistantly arranged on the rigid rod inside the blade root section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the blade root section; the M2 adjustment units are equidistantly arranged on the rigid rod inside the middle section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the middle section; the M3 adjustment units are equidistantly arranged on the rigid rod inside the blade tip section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the blade tip section.
[0008] When the blade is mounted on the hub, the hub does not need to have a pitch-changing hinge structure because the blade itself has a pitch-changing function.
[0009] As a further optimization solution of the multi-section blade with freely adjustable pitch according to the present invention, M1, M2 and M3 are all set to 1.
[0010] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: 1. Simple structure: The large and complex structure of the automatic tilt mechanism is eliminated, which reduces the mass of the rotor. The removal of the automatic tilt mechanism frees up additional design space. Since the blades have variable pitch function, the pitch hinge of the hub can also be eliminated to reduce the complexity of the structure. 2. Good safety: After the automatic tilt device is removed, there is no component that is easy to be damaged, such as a small pull rod. Safety is guaranteed; 3. High maneuverability: Compared with existing blade adjustment control schemes, the present invention can simultaneously control the root section, middle section (main lift section), and tip section of the blade, and can manipulate different blade sections, providing a higher maximum lift of the rotor under the same aerodynamic shape; 4. Low vibration and noise: The vibration and noise generated by the rotor can be reduced by adjusting the pitch changes of different parts of the blades when the rotor rotates. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a structural schematic diagram of the present invention.
[0012] In the figure, 1-fixed end, 2-root section, 3-first flexible section, 4-middle section, 5-second flexible section, 6-tip section. DETAILED DESCRIPTION
[0013] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings: The present invention can be implemented in many different forms and should not be considered to be limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the accompanying drawings, components are enlarged for clarity.
[0014] It should be understood that although the terms first, second, third, etc. may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from each other. Therefore, the first element, component, and / or part discussed below can become the second element, component, or part without departing from the teachings of the present invention.
[0015] like Figure 1 As shown, the present invention discloses a multi-section blade with freely adjustable pitch, comprising a fixed end, a blade root section, a first flexible section, a middle section, a second flexible section, a blade tip section, a rigid rod, N bearings, and an adjustment module, where N is a natural number greater than or equal to 1; The fixed end, the blade root section, the first flexible section, the middle section, the second flexible section, and the blade tip section are connected in sequence; The rigid rod is disposed in the beam of the blade, with one end fixedly connected to the fixed end and the other end sequentially passing through the root section, the first flexible section, the middle section, the second flexible section, and then extending into the tip section; the rigid rod can bend in the flapping direction, but is extremely rigid in the torsion direction and is almost impossible to bend; The N bearings are equidistantly arranged on the rigid rod, the inner rings are coaxially fixedly connected to the rigid rod, and the outer rings are fixedly connected to the inner wall of the internal beam of the blade through the bearing seat; The regulating module includes M1+M2+M3 regulating units, where M1, M2, and M3 are all natural numbers greater than or equal to 1; the regulating unit includes an electromagnetic coil and an excitation coil; the excitation coil is sleeved outside the electromagnetic coil and is coaxial with the electromagnetic coil, and can rotate after being driven by the electromagnetic coil; Among the M1+M2+M3 adjustment units, the M1 adjustment units are equidistantly arranged on the rigid rod inside the blade root section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the blade root section; the M2 adjustment units are equidistantly arranged on the rigid rod inside the middle section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the middle section; the M3 adjustment units are equidistantly arranged on the rigid rod inside the blade tip section, the electromagnetic coils are coaxially fixed to the rigid rod, and the excitation coils are fixed to the inner wall of the beam inside the blade tip section.
[0016] M1, M2, and M3 all take priority over 1.
[0017] When the blades are installed on the hub, the hub does not need a pitch hinge structure because the blades themselves have a pitch-changing function. The root section, middle section and tip section are all penetrated by a rigid rod that is integrated with the fixed end. Several drive coils are distributed on the rod. The first and second flexible sections serve as connections between the root section, middle section and tip section. The entire blade can adjust the rotor collective pitch by increasing or decreasing the power of all adjustment units at the same time, or by controlling the power of all adjustment units at the same frequency as the rotational speed to adjust the rotor cyclic pitch. In addition to realizing the basic functions of the automatic tilter, each blade segment can also be adjusted separately. For the root segment, when entering the backflow area, the power of the regulating unit in this segment can be reduced to reduce the pitch, thereby reducing the drag and negative lift generated in the backflow area. For the tip segment, when entering the stall area, the power of the regulating unit in the tip segment can be reduced to reduce the pitch (angle of attack) to avoid and weaken the stall phenomenon and the sudden increase in drag caused by shock waves and reduce the vibration generated by shock waves. For the middle segment (main lift segment), since it is not affected by the backflow and stall areas, the pitch (angle of attack) can be appropriately increased to increase the lift of the rotor. In addition, the angle changes of each blade segment can be adjusted and controlled by algorithms to reduce the vibration amplitude and noise of the rotor.
[0018] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such, will not be interpreted in an idealized or overly formal sense.
[0019] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A multi-stage propeller blade with freely adjustable pitch, characterized in that: It includes a fixed end, a blade root section, a first flexible section, a middle section, a second flexible section, a blade tip section, a rigid rod, N bearings, and an adjustment module, where N is a natural number greater than or equal to 1; The fixed end, the blade root section, the first flexible section, the middle section, the second flexible section, and the blade tip section are connected in sequence; The rigid rod is arranged in the beam of the blade, one end of which is fixedly connected to the fixed end, and the other end of which passes through the root section, the first flexible section, the middle section, the second flexible section in sequence and then extends into the tip section; The N bearings are equidistantly arranged on the rigid rod, the inner rings are coaxially fixedly connected to the rigid rod, and the outer rings are fixedly connected to the inner wall of the internal beam of the blade through the bearing seat; The regulating module comprises M1+M2+M3 regulating units, where M1, M2 and M3 are all natural numbers greater than or equal to 1; the regulating unit comprises an electromagnetic coil and an excitation coil; the excitation coil is sleeved outside the electromagnetic coil, is coaxial with the electromagnetic coil, and can rotate after being driven by the electromagnetic coil; Among the M1+M2+M3 adjustment units, the M1 adjustment units are equidistantly arranged on the rigid rod inside the root section, the electromagnetic coils are coaxially fixedly connected to the rigid rod, and the excitation coil is fixedly connected to the inner wall of the beam inside the root section; the M2 adjustment units are equidistantly arranged on the rigid rod inside the middle section, the electromagnetic coils are coaxially fixedly connected to the rigid rod, and the excitation coil is fixedly connected to the inner wall of the beam inside the middle section; the M3 adjustment units are equidistantly arranged on the rigid rod inside the tip section, the electromagnetic coils are coaxially fixedly connected to the rigid rod, and the excitation coil is fixedly connected to the inner wall of the beam inside the tip section.
2. The multi-stage propeller blade with freely adjustable pitch according to claim 1, characterized in that: M1, M2, and M3 are all set to 1.