Rotor wing periodic reducing device, control method and helicopter rotor wing blade device

Abstract

The invention discloses a rotor periodic reducing device, a control method and a helicopter rotor blade device. The crank main shaft is arranged in the center of a rotor wing, and a connecting disc is fixed on the crank main shaft; the connecting disc is connected with a sliding shaft through a connecting rod, the far end of the sliding shaft is fixedly connected with rotor blades, and the sliding shaft can axially slide in the propeller hub; and a propeller hub gear is arranged at the outer bottom of the propeller hub and is meshed with a power gear driven by an engine, so that the rotor system is driven to rotate. In the rotating process of the rotor wing, the crank drives the connecting rod to move periodically, the sliding shaft is driven to move back and forth, and then the rotating radius of the paddle is driven to change periodically. The rotating radius of the forward paddle is reduced, and the linear speed of the forward paddle is reduced; the radius of the trailing blade is increased, the linear speed of the trailing blade is increased, the problem that the lift force distribution of the forward blade and the trailing blade of the rotor wing is not uniform is solved, the maximum flight speed of a helicopter is remarkably increased, the flight stability and efficiency in a high-speed state are improved, and the rotor wing is particularly suitable for the fields of high-speed helicopters, composite rotor wing aircrafts and the like.

Description

Technical Field

[0001] The invention relates to the technical field of aviation systems, and in particular to a rotor periodic diameter-changing device, a control method and a helicopter rotor blade device. Background Art

[0002] The maximum forward flight speed of mainstream helicopters is around 300km / h. Generally speaking, the normal cruising speed is between 200-240km / h, and generally does not exceed 280km / h. Compared with the flight speed of fixed-wing aircraft of 300-800km / h, the flight speed of helicopters is not outstanding. The main reason for this phenomenon is that the flight speed of helicopters is severely limited by the linear speed of the rotor blade tip. The rotor of a helicopter needs to rotate at high speed to generate lift. Even if the helicopter is hovering, the linear speed of the rotor blade tip needs to reach 400~600km / h to generate sufficient lift. If the helicopter flies forward, even at a speed of only 300km / h, the oncoming airflow speed will be superimposed on the linear speed of the forward-rotating rotor blade (forward blade), which can easily cause the blade tip to reach the transonic range (greater than 0.75 Mach), resulting in a significant drop in efficiency and severe vibration; as the rotor rotates, the forward blade will turn to the rear, and the blade linear speed will be subtracted from the airflow speed, causing a sharp drop in blade lift. This situation causes the lift generated by the helicopter rotor to be unbalanced left and right during one rotation (propeller disc), increasing the difficulty of control. In addition, as the forward flight speed increases, the airflow speed on the helicopter's rotor blades will change more and more violently, causing great vibration and noise to the high-speed forward-flying helicopter, and more seriously damaging the fuselage structure. These defects seriously restrict the further improvement of the forward flight speed of the helicopter. In order to overcome the above difficulties, high-rigidity coaxial twin-propeller technology has emerged. Two rotors with opposite rotation directions are arranged up and down, rotating around the same axis, balancing the lift on the rotor disc; at the same time, the precise aerodynamic design and control of the high-rigidity rotor can reduce vibration, thereby increasing the upper limit of the helicopter's forward flight speed (doctoral dissertation: Research on the aerodynamic characteristics of high-speed helicopter coaxial rigid twin rotors based on CFD methods; Research on aerodynamic characteristics of high-speed helicopter rigid rotors with large forward ratios). However, it should be pointed out that the use of this technology can effectively reduce negative aerodynamic effects such as vibration and lift imbalance, but it still cannot avoid the supersonic phenomenon of the blade tip caused by the superposition of the forward blade and the forward flight speed, so the improvement of the upper limit of the forward flight speed is relatively limited. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a rotor periodic variable diameter device and a control method. The feature is that when the rotor rotates, it can automatically change the rotation radius of each independent blade, for example, reducing the rotation radius and linear velocity of the advancing blade, and increasing the rotation radius and linear velocity of the retreating blade, thereby increasing the maximum allowable flight speed of the helicopter and improving the lift distribution of the rotor disk.

[0004] To achieve the above object, the present invention provides the following technical solutions. A rotor periodic variable diameter device includes: A crank main shaft, arranged at the top of the helicopter; A connecting disk, installed on the crank of the crank main shaft; A connecting rod, one end of which is connected to the connecting disk; A sliding shaft, connected to the other end of the connecting rod, and the other end of the sliding shaft is installed with a rotor blade; A hub, sleeved outside the crank main shaft, the connecting disk and the connecting rod, and the sliding shaft passes through the opening on the side of the hub, and the crank main shaft passes through the bottom center of the hub; A hub gear, installed at the center outside the bottom of the hub, and coaxial with the crank main shaft; A power gear, meshing with the hub gear, powered by the helicopter engine, so as to drive the hub gear and drive the hub to rotate; Preferably, a connecting disk gear is installed on the connecting disk; a synchronous gear is installed on the hub; a direction-changing gear is installed on the crank of the crank main shaft and meshes with the connecting disk gear and the synchronous gear, so that the connecting disk and the hub rotate at the same speed and in the same direction.

[0005] Preferably, a crank gear is installed on the crank main shaft; a control gear is arranged on the helicopter control mechanism and meshes with the crank gear, so as to change the orientation of the crank main shaft and control the helicopter.

[0006] The present invention also provides a control method for a rotor periodic variable diameter device, which is characterized by including the following steps: When in the hover state, the control gear drives the crank gear to rotate, thereby driving the crank of the crank main shaft to face the nose direction of the helicopter. At this time, the blade in the nose direction of the helicopter has a larger rotation radius, and the blade in the tail direction has a smaller rotation radius. Through prior arrangement, the overall center of gravity of the helicopter coincides with the center of rotor lift in the vertical direction, so that the gravity and lift of the helicopter are balanced.

[0007] In the high-speed forward flight state, the control gear drives the crank gear to rotate, driving the crank main shaft, and making the crank face the side of the retreating blade of the helicopter. At this time, when observed from the side, the center of gravity of the helicopter is in front of the center of the rotor lift force, and the moments of gravity and lift are conducive to the helicopter generating a nose-down movement, thereby increasing the pull force of the rotor towards the front.

[0008] The present invention also discloses a helicopter rotor blade device, which is characterized in that: the device includes the above-mentioned rotor periodic variable diameter device. Beneficial effects

[0009] When the helicopter rotor is rotating, it automatically changes the rotation radius of each independent blade, reduces the rotation radius and linear velocity of the advancing blade, and increases the rotation radius and linear velocity of the retreating blade, thereby increasing the maximum allowable flight speed of the helicopter and also improving the lift distribution of the blade disc.

[0010] The control method of the rotor periodic variable diameter device will automatically generate the required nose-down moment when the helicopter is flying forward. Brief description of the drawings

[0011] Figure 1 The figure shows a top view of the present invention; Figure 2 The figure shows an axonometric view of the present invention.

[0012] In the figure, 1 - crank main shaft, 2 - connecting disc, 3 - connecting rod, 4 - sliding shaft, 5 - hub, 6 - synchronous gear, 7 - direction-changing gear, 8 - connecting disc gear, 9 - power gear, 10 - hub gear, 11 - crank gear, 12 - control gear. Detailed implementation manners

[0013] A rotor periodic variable diameter device, such as Figure 1As shown in the figure, the rotor periodic pitch-changing device includes a crank main shaft 1. A connecting disk 2 is installed on the crank of the crank main shaft 1 and can rotate freely. A connecting rod 3 is installed on the connecting disk 2. The other end of the connecting rod 3 is connected to a sliding shaft 4, and the other end of the sliding shaft 4 is fixed with a rotor blade of the helicopter. The hub 5 can be made into a hollow thin-shell structure, accommodating the crank of the crank main shaft 1, the connecting disk 2, and the connecting rod 3 therein. The sliding shaft 4 passes through the opening on the side of the hub 5 and forms a sliding fit with the hub 5. At the center of the bottom of the hub 5, a hub gear 10 is fixed. The crank main shaft 1 passes through the hub 5 and the hub gear 10 and is installed on the top of the helicopter. The power gear 9 is driven by the helicopter engine and meshes with the hub gear 10, so as to drive the hub 5 to rotate relative to the crank main shaft 1. The rotational movement of the hub 5 is transmitted to the sliding shaft 4, thereby driving the rotation of the rotor blade. Since the sliding shaft 4 is indirectly connected to the crank of the crank main shaft 1 through the connecting rod 3 and the connecting disk 2, when the rotor rotates, the eccentricity formed by the crank will continuously drive the sliding shaft 4 to axially slide relative to the hub 5 through the connecting rod 3. Every time the hub 5 rotates one week, the sliding shaft 4 will also slide back and forth once, thus achieving the effect of periodically changing the rotation radius of the blade.

[0014] Under ideal conditions, the connecting disk 2 will rotate synchronously with the hub 5 under the drive of the connecting rod 3. However, in reality, friction, interference, etc. are inevitable. Therefore, the connecting disk will not rotate synchronously with the hub 5 as ideally, resulting in unsmooth movement between the connecting rod 3, the sliding shaft 4, etc., affecting the rotor periodic pitch-changing effect. Therefore, a synchronizing gear 6 is provided inside the hub 5 and meshes with a reversing gear 7, and the reversing gear 7 is installed on the crank of the crank main shaft 1. A connecting disk gear 8 is fixed on the connecting disk 2 and meshes with the reversing gear 7. The number of teeth of the synchronizing gear 6 and the connecting disk gear 8 is equal. Therefore, when the hub 5 rotates, the synchronizing gear 6 will drive the connecting disk gear 8 through the reversing gear 7, causing the connecting disk 2 and the hub 5 to rotate in the same direction and at the same speed.

[0015] In the present invention, the crank main shaft is fixed on the top of the helicopter, and the root of the blade is connected to the connecting disk of the crank through a connecting rod. The hub and the crank main shaft are coaxial, and under the drive of the engine, the blade rotates at an angular velocity Ω. Due to the eccentricity A between the crank and the main shaft, during one rotation of the blade, the rotation radius will change periodically. To achieve beneficial effects, the crank should face the side of the retreating blade. Assuming the blade length is R and the radius of the connecting disk is ignored, the tip linear velocity of the advancing blade is:

[0016] The tip linear velocity of the retreating blade is:

[0017] Obviously , meaning that the tip linear velocity of the advancing blade is smaller and that of the retreating blade is larger, and . As is well known, when the forward flight speed of the helicopter V is too high, the tip linear velocity of the advancing side blade will be superimposed with the forward flight speed V , thus entering the supersonic region. A series of problems such as vibration and sudden change of flow field will cause great damage to the helicopter structure. Therefore, the forward flight speed of the helicopter V is always less than the speed of sound V s and the difference between the tip linear velocity of the advancing blade V f , that is:

[0018] This technology reduces the tip linear velocity of the advancing blade and delays the time when the tip of the advancing side blade enters the supersonic region. Therefore, when the speed of sound remains unchanged, the upper limit of the forward flight speed of the helicopter can be increased, allowing the helicopter to fly forward at a higher speed. At the same time, because the retreating side blade of the helicopter has a higher tip linear velocity , it will generate a greater lift force, improving the lift distribution of the rotor disk.

[0019] As Figure 2 shown, the control device of the helicopter is connected with a control gear 12, which meshes with a crank gear 11. The crank gear 11 and a crank main shaft 1 are fixed. The control gear 12 can drive the crank gear 11 to drive the rotation of the crank main shaft 1, thereby changing the orientation of the crank.

[0020] The control method of the rotor periodic variable diameter device disclosed by the present invention can generate the required control torque by changing the orientation of the crank. When the helicopter hovers, it is required that the "rotor disk" is completely horizontal, so that the lift force is vertically upward and coincides with the center of gravity. At this time, through the control gear 12, the crank of the crank main shaft 1 is driven to face forward, so that the blade rotation radius in the nose direction is larger and the blade rotation radius in the tail direction is smaller, and the rotor disk lift force is on the longitudinal axis of the helicopter; then, by means of pre-increasing the counterweight, changing the mass distribution, etc., the center of gravity of the helicopter is adjusted to be directly below the lift force, meeting the requirements of stable hovering. When the helicopter needs to fly forward, the control gear 12 drives the crank to face the side of the helicopter, the side of the retreating blade. At this time, the lift force moves to the side rear, forming two torques: a roll torque and a pitching torque. The roll torque can be eliminated by control means such as the periodic pitch change of the helicopter itself; and the pitching torque can control the helicopter to tilt forward automatically, so that the lift force generates a component force forward, driving the helicopter to fly forward.

[0021] The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, various changes and improvements will occur to the present invention, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection required by the present invention is defined by the appended claims and their equivalents.

Claims

1. A rotor periodic diameter-changing device, characterized in that: A crank main shaft (1), the lower end of which can be connected to a helicopter transmission system; A connecting disk (2), fixedly arranged at the crank end of the crank main shaft (1); A connecting rod (3), one end of which is hinged to the connecting disk (2), and the other end is hinged to the proximal end of a sliding shaft (4); A sliding shaft (4), which can reciprocally slide along the radial direction through a guiding hole of a hub (5), and the distal end of the sliding shaft is fixedly connected to a rotor blade; A hub (5), coaxially sleeved outside the crank main shaft (1), a main shaft hole is provided at the center of its bottom, and a guiding hole for the radial penetration of the sliding shaft (4) is provided on the side wall; A hub gear (10), coaxially fixed outside the bottom of the hub (5); A power gear (9), meshing with the hub gear (10) and driven by an engine; Wherein, when the hub gear (10) rotates, it drives the sliding shaft (4) to rotate synchronously, and the connecting rod (3) drives the sliding shaft (4) to reciprocally move in the radial direction, so that the rotation radius of the rotor blade changes periodically with the rotation of the rotor.

2. The device according to claim 1, wherein: A connecting disk gear (8) is circumferentially arranged on the connecting disk (2), a synchronous gear (6) is arranged on the hub (5), and a direction-changing gear (7) is arranged at the crank end. The direction-changing gear (7) meshes with the synchronous gear (6) and the connecting disk gear (8) at the same time to keep the connecting disk (2) and the hub (5) rotating at the same speed and in the same direction.

3. The device according to claim 1, characterized in that: A crank gear (11) is arranged on the crank main shaft (1), and a helicopter control mechanism is provided with a control gear (12) and meshes with the crank gear (11) to adjust the crank phase and control the helicopter.

4. A control method for a swashplate variable diameter device according to any one of claims 1-3, characterized in that, Including the following steps: In the hovering state, the crank gear (11) is driven to rotate by the control gear (12), the crank end of the crank main shaft (1) is adjusted to face the nose direction, so that the rotation radius of the blade in the nose direction increases, and the rotation radius of the blade in the tail direction decreases. Through pre-design, the overall center of gravity of the helicopter coincides with the center of rotor lift in the vertical direction, so that the gravity and lift of the helicopter are balanced; In the high-speed forward flight state, the crank gear (11) is driven to rotate by the control gear (12), and the crank end of the crank main shaft (1) is adjusted to face the side of the retreating blade, so as to form a moment for pitching the nose in the blade disk plane and increase the forward thrust.

5. A helicopter rotor blade device, characterized in that: The device includes the rotor periodic diameter-changing device according to any one of claims 1-3, and is controlled according to the method described in claim 4.

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