A helicopter rotor system

Abstract

The application provides a helicopter rotor system, wherein a cavity in the inside of a ring-shaped shell is provided with a ring-shaped cabin, a central space in the outside is provided with a main rotor structure through a main speed reducer support frame, a rear end is provided with a tail rotor cabin through a tail rotor shell, and a tail rotor is arranged in the tail rotor cabin; an engine is arranged at the rear of the ring-shaped cabin, outputs power to the tail rotor through a power shaft in the rear direction, outputs power to the main speed reducer through a transmission shaft in the front direction, and transmits the power after reduction to a main rotor hub and main rotor blades through a main rotor shaft; a small pull rod is hinged on an outer edge fork of a moving ring through a ball bearing at the lower end and is hinged on a horizontal shaft at the outer end of the main rotor blade through a ball bearing at the upper end; a plurality of rudders are evenly distributed on the same horizontal plane and are vertically installed on the main speed reducer support frame; the application adopts a non-open, supported and limited wing tip design, so that the linear speed of the wing tip of the main rotor of the helicopter can easily break through the sound speed without strong vibration, and a new scheme is provided for improving the speed and load of the helicopter.

Description

Technical Field

[0001] This invention belongs to the field of aviation technology, and in particular relates to a helicopter rotor system. Background Technology

[0002] The technical requirement that the linear velocity of the helicopter main rotor tip should not exceed the speed of sound has significantly limited the improvement of helicopter speed. The main reason why the linear velocity of the helicopter main rotor tip should not exceed the speed of sound is that the wingtip is open, unsupported, and without limit. Once the linear velocity of the wingtip approaches or exceeds the speed of sound, strong flutter will occur, affecting flight quality and causing fatigue to the rotor blade structure. After a certain degree and a certain period of time, the flutter will pose a risk of damage to the aircraft.

[0003] Currently, breakthroughs in helicopter speed improvement are mainly focused on three areas: first, using tail thruster mode; second, rigid hub rotor mode; and third, using tilt rotor mode. However, these three approaches are still being pursued within the technical constraint that the rotor tip linear speed cannot exceed the speed of sound. Therefore, helicopter speed increases are limited, and some payload capacity is sacrificed in the process. Summary of the Invention

[0004] To address the issue of increasing helicopter speed in existing technologies, this invention provides a helicopter rotor system with a unique structure. Employing a non-open, supported, and limited-position wingtip design, this system allows the helicopter main rotor wingtip linear velocity to easily exceed the speed of sound without severe flutter, providing a new solution for simultaneously increasing helicopter speed and payload. The technical solution is as follows:

[0005] In a first aspect, a helicopter rotor system is provided, comprising: an annular nacelle 1, an annular shell 2, a torsion arm 4, a main rotor blade 6, a main rotor hub 7, a main rotor shaft 8, a large ball joint core 9, a large ball joint ring 10, a tail rotor shell 11, a small tie rod 12, a tail rotor nacelle 13, a tail rotor 14, a power shaft 15, an engine 16, a drive shaft 17, a main gearbox support frame 18, a moving ring 19, a main gearbox 20, a stationary ring 21, an anti-torsion arm 22, and multiple servo motors 23;

[0006] Among them, the annular shell 2 is the support structure of the entire device. The annular chamber 1 is provided in the internal cavity of the annular shell 2. The main rotor structure is arranged in the external central space through the main reducer support frame 18. The tail rotor 13 is formed at the rear end through the tail rotor shell 11. The tail rotor 14 is provided in the tail rotor 13.

[0007] The main reducer 20 is fixed at the center of the main reducer support frame 18. The upper end of the main reducer 20 extends out of the main rotor shaft 8. The upper end of the main rotor shaft 8 is connected to the main rotor hub 7. The inner end of the main blade 6 is hinged to the outer edge of the main rotor hub 7.

[0008] The engine 16 is located at the rear of the annular compartment 1. The engine 16 outputs power to the tail rotor 14 through the power shaft 15. The engine 16 outputs power to the main reduction gear 20 through the drive shaft 17. The main reduction gear 20 transmits the reduced power to the main rotor hub 7 and the main rotor blade 6 through the main rotor shaft 8.

[0009] A large ball joint core 9 is provided between the main reducer 20 and the main propeller hub 7;

[0010] The large ball hinge ring 10 is fixed to the stationary ring 21, and the stationary ring 21 is hinged to the moving ring 19. The moving ring 19 and the stationary ring 21 can only rotate relative to each other. The other dimensions are restricted by the structure between the moving ring 19 and the stationary ring 21. Except for relative rotation, the moving ring 19 and the stationary ring 21 follow each other in other movements.

[0011] The outer end of the torque arm 4 is hinged to the outer edge of the moving ring 19, and the inner end of the torque arm 4 is clamped on the main rotor shaft 8. Its main function is to completely transmit the rotational motion of the main rotor shaft 8 to the moving ring 19, so that the moving ring 19 maintains the same relative position and rotational speed with the main rotor shaft 8, while not hindering the up and down movement of the moving ring 19 and its rotation around the large ball hinge core 9.

[0012] The outer end of the anti-torsion arm 22 is hinged to the outer edge of the stationary ring 21, and the inner end of the anti-torsion arm 22 is fixed to the housing of the main reducer 20. Its main function is to prevent the stationary ring 21 from rotating and to prevent the stationary ring 21 from being driven by the passive ring 19 to rotate. At the same time, it does not hinder the up and down movement of the moving and stationary rings 21 and their rotation around the large ball hinge core 9.

[0013] The small tie rod 12 is hinged to the outer edge of the moving ring 19 via a ball bearing at its lower end, and to the outer transverse shaft of the main blade 6 via a ball bearing at its upper end. The inner transverse shaft of the main blade 6 is located at the leading edge of the blade, and the outer transverse shaft of the main blade 6 is located at the trailing edge of the blade. There is a lever arm between the inner and outer transverse shafts of the main blade 6. When the small tie rod 12 pushes and pulls the outer transverse shaft of the main blade 6 to move up and down, the main blade 6 deflects around the elastic ball bearing connected to its inner transverse shaft, and the angle of attack of the main blade 6 changes, thus realizing the pitch change of the main blade 6.

[0014] Multiple servo motors 23 are evenly distributed on the same horizontal plane and vertically mounted on the main reducer support frame 18. The actuator of the servo motor 23 is hinged to the outer edge of the stationary ring 21 via a ball bearing at its upper end.

[0015] The annular compartment 1, annular shell 2, main rotor hub 7, main rotor shaft 8, large ball joint core 9, large ball joint ring 10, moving ring 19, main reducer 20, and stationary ring 21 are coaxially arranged.

[0016] Optionally,

[0017] The outer end of the torque arm 4 is hinged to the outer edge of the moving ring 19 via a ball bearing;

[0018] The outer end of the anti-torsion arm 22 is hinged to the outer edge of the stationary ring 21 via a ball bearing.

[0019] Among them, the large ball hinge ring 10 is fixedly connected to the stationary ring 21 through the tilter strut 5, and the stationary ring 21 is hinged to the moving ring 19 through the large bearing 3.

[0020] Among them, the large ball hinge core 9 is a structure in which a hollow ball is fixedly fitted on the outside of a hollow column. The hollow column structure of the large ball hinge core 9 is fitted on the main rotor shaft 8 and can slide up and down along the main rotor shaft 8. The hollow ball structure of the large ball hinge core 9 is wrapped inside the large ball hinge ring 10, forming a spherical clearance fit with the large ball hinge ring 10. The large ball hinge ring 10 can rotate around the hollow ball structure of the large ball hinge core 9, and can also push the large ball hinge core 9 to slide up and down along the main rotor shaft 8.

[0021] Among them, the small tie rod 12 is a two-force rod structure with ball bearings at both ends and a solid rod in the middle, which needs to bear both tension and pressure.

[0022] The main blade 6 consists of inner and outer transverse shafts and a middle airfoil section; the inner transverse shaft of the main blade 6 is hinged to the outer edge of the main blade hub 7 by a flexible ball bearing, and the outer transverse shaft of the main blade 6 is hinged to the upper end of the small tie rod 12 by a flexible ball bearing.

[0023] Among them, there are 3 servo motors in servo 23.

[0024] When the actuators of the three servos 23 extend and retract by the same length in sync, each small lever 12 pushes and pulls the corresponding main rotor blade 6 to produce the same pitch change, thereby changing the collective pitch. The lift of the main rotor increases or decreases uniformly, and the helicopter achieves the motion of ascending or descending.

[0025] in,

[0026] When the actuators of the three servos 23 extend or retract to different lengths, each small lever 12 pushes or pulls the corresponding main rotor blade 6 to produce different pitch changes, thereby achieving periodic changes in the rotor pitch. The lift of the main rotor increases or decreases on the corresponding side, and the helicopter achieves pitch and roll attitude movements.

[0027] The beneficial effects of this invention are at least as follows:

[0028] (1) This invention changes the form of the traditional helicopter main rotor blade pitch change, changing the pitch from the blade root edge distance to the blade tip pitch change, which increases the constraint at the blade tip. It adopts a non-open, supported, and limited wingtip design, which allows the helicopter main rotor wingtip linear velocity to easily break the speed of sound without strong flutter, providing a new solution for the dual improvement of helicopter speed and load.

[0029] (2) The present invention adopts a ring cabin structure design, which not only adapts to the new main rotor structure design, but also forms a new configuration of helicopter internal space structure, greatly increasing the internal space of the helicopter.

[0030] (3) This invention conforms to the general logic and principles of helicopter structural design, control, and aerodynamics, and is scientific and feasible. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure of the present invention. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0033] This invention provides a helicopter rotor system; please refer to [link / reference]. Figure 1 It includes: annular compartment 1, annular shell 2, large bearing 3, torsion arm 4, swashplate strut 5, main rotor blade 6, main rotor hub 7, main rotor shaft 8, large ball joint core 9, large ball joint ring 10, tail rotor shell 11, small tie rod 12, tail rotor compartment 13, tail rotor 14, power shaft 15, engine 16, drive shaft 17, main reducer support frame 18, moving ring 19, main reducer 20, stationary ring 21, anti-torsion arm 22, and servo motor 23.

[0034] The annular shell 2 is the support structure for the entire device. The internal cavity of the annular shell 2 is the annular compartment 1, which can be used as the cockpit, passenger and cargo compartment, engine compartment, and equipment compartment. The main rotor structure is arranged in the central space outside the annular shell 2 through the main gearbox support frame 18. The tail rotor compartment 13 is formed at the rear end of the annular shell 2 through the tail rotor shell 11, and the tail rotor 14 is arranged in the tail rotor compartment 13.

[0035] Engine 16 is located at the rear of the annular compartment 1. Engine 16 outputs power to the tail rotor 14 through the power shaft 15. Engine 16 outputs power to the main gearbox 20 through the drive shaft 17. The main gearbox 20 transmits the reduced power to the main rotor hub 7 and the main rotor blade 6 through the main rotor shaft 8.

[0036] The main reducer 20 is fixed at the center of the main reducer support frame 18. The upper end of the main reducer 20 extends out of the main rotor shaft 8. The upper end of the main rotor shaft 8 is connected to the main rotor hub 7. The transverse shaft at the inner end of the main rotor blade 6 is hinged to the outer edge of the main rotor hub 7 through an elastic ball bearing.

[0037] A large spherical hinge core 9 is installed between the main reducer 20 and the main rotor hub 7. The large spherical hinge core 9 is a structure in which a hollow sphere is fixedly fitted onto the outside of a hollow column. The hollow column structure of the large spherical hinge core 9 is fitted onto the main rotor shaft 8 and can slide up and down along the main rotor shaft 8. The hollow spherical structure of the large spherical hinge core 9 is enclosed within a large spherical hinge ring 10, forming a spherical clearance fit with the large spherical hinge ring 10. The large spherical hinge ring 10 can both rotate around the hollow spherical structure of the large spherical hinge core 9 and push the large spherical hinge core 9 to achieve up and down sliding along the main rotor shaft 8.

[0038] The annular compartment 1, annular shell 2, large bearing 3, main rotor hub 7, main rotor shaft 8, large ball joint core 9, large ball joint ring 10, moving ring 19, main reducer 20, and stationary ring 21 are all coaxial.

[0039] The large ball joint 10 is fixed to the stationary ring 21 via the tilter strut 5, and the stationary ring 21 is hinged to the moving ring 19 via the large bearing 3. The moving ring 19 and the stationary ring 21 can only rotate relative to each other. Other dimensions are restricted by the structure between the moving ring 19 and the stationary ring 21. Apart from relative rotation, the moving ring 19 and the stationary ring 21 follow each other in other movements.

[0040] The outer end of the torque arm 4 is hinged to the outer edge of the moving ring 19 via a ball bearing, and the inner end of the torque arm 4 is clamped onto the main rotor shaft 8. Its main function is to completely transmit the rotational motion of the main rotor shaft 8 to the moving ring 19, so that the moving ring 19 maintains the same relative position and rotational speed with the main rotor shaft 8, while not hindering the up-and-down movement of the moving ring 19 and its rotation around the large ball hinge core 9.

[0041] The outer end of the anti-torsion arm 22 is hinged to the outer edge of the stationary ring 21 via a ball bearing, and the inner end of the anti-torsion arm 22 is fixed to the housing of the main reducer 20. Its main function is to hold the stationary ring 21 in place and prevent it from rotating, thus preventing the stationary ring 21 from being driven to rotate by the passive ring 19. At the same time, it does not hinder the up-and-down movement of the moving and stationary rings 21 or their rotation around the large ball hinge core 9.

[0042] The tie rod 12 is hinged to the outer edge of the moving ring 19 via a ball bearing at its lower end, and to the outer transverse shaft of the main blade 6 via a ball bearing at its upper end. The inner transverse shaft of the main blade 6 is located at the leading edge of the blade, and the outer transverse shaft of the main blade 6 is located at the trailing edge of the blade. Therefore, there is a lever arm between the inner and outer transverse shafts of the main blade 6. When the tie rod 12 pushes and pulls the outer transverse shaft of the main blade 6 to move up and down, the main blade 6 deflects around the elastic ball bearing connected to its inner transverse shaft, and the angle of attack of the main blade 6 changes, thus realizing the pitch change of the main blade 6.

[0043] In one embodiment, three servo motors 23 are evenly distributed on the same horizontal plane and vertically mounted on the main reducer support frame 18. The actuators of the servo motors 23 are hinged to the outer edge of the stationary ring 21 via ball bearings at their upper ends. When the actuators of the three servo motors 23 extend and retract by the same length synchronously, each small lever 12 pushes and pulls the corresponding main rotor blade 6 to produce the same pitch change, thus realizing the change in collective pitch. The lift of the main rotor increases or decreases uniformly, and the helicopter can achieve ascent or descent.

[0044] When the actuators of the three servos 23 extend or retract to different lengths, each small lever 12 pushes or pulls the corresponding main rotor blade 6 to produce different pitch changes, thus realizing the periodic change of the rotor pitch. The lift of the main rotor increases or decreases on the corresponding side, and the helicopter can achieve pitch, roll and other attitude movements.

[0045] The operation process of this invention is as follows:

[0046] (1) After the engine 16 starts, the engine 16 outputs power to the tail rotor 14 through the power shaft 15, and outputs power to the main reducer 20 through the drive shaft 17. The main reducer 20 transmits the reduced power to the main rotor hub 7 and the main rotor blade 6 through the main rotor shaft 8. The rotation of the tail rotor 14 generates a counter-torque force for the device, and the rotation of the main rotor blade 6 provides lift for the device.

[0047] (2) The outer end of the torque arm 4 is hinged to the outer edge of the moving ring 19 via a ball bearing, and the inner end of the torque arm 4 is clamped on the main rotor shaft 8. Its main function is to completely transmit the rotational motion of the main rotor shaft 8 to the moving ring 19, so that the moving ring 19 maintains the same relative position and rotational speed with the main rotor shaft 8, while not hindering the up and down movement of the moving ring 19 and its rotation around the large ball hinge core 9.

[0048] (3) The outer end of the anti-torsion arm 22 is hinged to the outer edge of the stationary ring 21 via a ball bearing, and the inner end of the anti-torsion arm 22 is fixed to the housing of the main reducer 20. Its main function is to hold the stationary ring 21 in place and prevent it from rotating, thus preventing the stationary ring 21 from being driven by the passive ring 19. At the same time, it does not hinder the up-and-down movement of the moving and stationary rings 21 and their rotation around the large ball hinge core 9.

[0049] (4) When it is necessary to achieve variable collective pitch of the main rotor blade 6, the actuators of the three servo motors 23 extend and retract by the same length simultaneously, and the actuators of the three servo motors 23 push and pull the stationary ring 21 simultaneously. The stationary ring 21 transmits the motion to the moving ring 19. The moving ring 19 pushes and pulls the large ball joint ring 10 through the swashplate strut 5. The large ball joint ring 10 slides up and down along the main rotor shaft 8, so that the moving ring 19 transmits the motion to the small tie rod 12. When the small tie rod 12 pushes and pulls the outer transverse axis of the main rotor blade 6 to move up and down, the main rotor blade 6 deflects around the elastic ball bearing connected to its inner transverse axis, and the angle of attack of the main rotor blade 6 changes, thus achieving variable pitch of the main rotor blade 6;

[0050] Each small lever 12 pushes and pulls the corresponding main rotor blade 6 to produce the same pitch change, thus realizing the change in collective pitch. The lift of the main rotor increases or decreases uniformly, and the helicopter can achieve ascending or descending motion.

[0051] (5) When it is necessary to achieve periodic pitch change of the main rotor blade 6, the actuators of the three servo motors 23 extend and retract by different lengths, and the actuators of the three servo motors 23 push and pull the stationary ring 21 respectively. The stationary ring 21 transmits the motion to the moving ring 19. The moving ring 19 rotates around the large ball joint core 9 through the swashplate strut 5, so that the moving ring 19 transmits the motion to the small tie rod 12. When the small tie rod 12 pushes and pulls the outer transverse axis of the main rotor blade 6 to move up and down, the main rotor blade 6 deflects around the elastic ball bearing connected to its inner transverse axis, and the angle of attack of the main rotor blade 6 changes, thus achieving pitch change of the main rotor blade 6. Each small tie rod 12 pushes and pulls the corresponding main rotor blade 6 to achieve different pitch changes, thus achieving periodic pitch changes. The lift of the main rotor increases or decreases on the corresponding side, and the helicopter can achieve pitch, roll and other attitude movements.

[0052] (6) The total pitch motion and periodic pitch motion of the main blade 6 can be realized synchronously, and its principle is consistent with the principle of the total pitch motion and periodic pitch motion of the main blade 6.

[0053] The key points of this invention are as follows:

[0054] (1) The hollow column structure of the large ball hinge core 9 is fitted onto the main rotor shaft 8 and can slide up and down along the main rotor shaft 8. The hollow ball structure of the large ball hinge core 9 is wrapped inside the large ball hinge ring 10, forming a spherical clearance fit with the large ball hinge ring 10. The large ball hinge ring 10 can rotate around the hollow ball structure of the large ball hinge core 9, and can also push the large ball hinge core 9 to slide up and down along the main rotor shaft 8;

[0055] (2) The annular compartment 1, annular shell 2, large bearing 3, main rotor hub 7, main rotor shaft 8, large ball hinge core 9, large ball hinge ring 10, moving ring 19, main reducer 20, and stationary ring 21 are all coaxial.

[0056] (3) The large ball hinge ring 10 is fixed to the stationary ring 21 through the tilter strut 5, and the stationary ring 21 is hinged to the moving ring 19 through the large bearing 3. The moving ring 19 and the stationary ring 21 can only rotate relative to each other. Other dimensions are restricted by the structure between the moving ring 19 and the stationary ring 21. Except for relative rotation, the moving ring 19 and the stationary ring 21 keep following each other in other movements.

[0057] (4) The transverse axis of the inner end of the main blade 6 is arranged at the leading edge of the blade, and the transverse axis of the outer end of the main blade 6 is arranged at the trailing edge of the blade. Therefore, there is a lever arm between the transverse axes of the inner and outer ends of the main blade 6. When the small pull rod 12 pushes and pulls the transverse axis of the outer end of the main blade 6 to move up and down, the main blade 6 deflects around the elastic ball bearing connected to its inner transverse axis, and the angle of attack of the main blade 6 changes, thus realizing the pitch change of the main blade 6.

[0058] (5) When the actuators of the three servo motors 23 extend and retract by the same length in sync, each small lever 12 pushes and pulls the corresponding main rotor blade 6 to produce the same pitch change, that is, the collective pitch is changed, the lift of the main rotor increases or decreases uniformly, and the helicopter can achieve the movement of ascending or descending.

[0059] (6) When the actuators of the three servo motors 23 extend and retract to different lengths, each small lever 12 pushes and pulls the corresponding main rotor blade 6 to produce different pitch changes, thus realizing the periodic change of the rotor pitch. The lift of the main rotor increases or decreases on the corresponding side, and the helicopter can achieve pitch, roll and other attitude movements.

[0060] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A helicopter rotor system, characterised in that, Comprise: Annular cabin (1), annular shell (2), torsion arm (4), main blade (6), main hub (7), main rotor shaft (8), large spherical hinge core (9), large spherical hinge ring (10), tail rotor shell (11), small pull rod (12), tail rotor cabin (13), tail rotor (14), power shaft (15), engine (16), transmission shaft (17), main reducer support frame (18), moving ring (19), main reducer (20), fixed ring (21), anti-torsion arm (22), a plurality of rudders (23); Wherein, the annular shell (2) inside cavity is provided with annular cabin (1), the outer center space is arranged main rotor structure through main reducer support frame (18), the rear end is formed through tail rotor shell (11) tail rotor cabin (13), tail rotor cabin (13) is equipped with tail rotor (14); The main reducer (20) is fixed in the center of the main reducer support frame (18), the upper end of the main reducer (20) extends the main rotor shaft (8), the upper end of the main rotor shaft (8) is connected with the main hub (7), and the inner end of the main blade (6) is hinged to the outer edge of the main hub (7). The engine (16) is arranged at the rear of the annular cabin (1), the engine (16) is outputted power to the tail rotor (14) through the power shaft (15) to the rear, the engine (16) is outputted power to the main reducer (20) through the transmission shaft (17) to the front, and the main reducer (20) transmits the power after reduction to the main hub (7) and the main blade (6) through the main rotor shaft (8); The main reducer (20) and the main hub (7) are provided with a large spherical hinge core (9); the large spherical hinge ring (10) is fixedly connected with the fixed ring (21), the fixed ring (21) is hinged with the moving ring (19); the outer end of the torsion arm (4) is hinged to the outer edge of the moving ring (19), and the inner end of the torsion arm (4) is clamped on the main rotor shaft (8); the outer end of the anti-torsion arm (22) is hinged to the outer edge of the fixed ring (21), and the inner end of the anti-torsion arm (22) is fixedly connected with the main reducer (20) shell; the small pull rod (12) is hinged to the outer edge of the moving ring (19) through the ball bearing at the lower end, and is hinged to the outer end horizontal shaft of the main blade (6) through the ball bearing at the upper end; the inner end horizontal shaft of the main blade (6) is arranged at the front edge of the blade, and the outer end horizontal shaft of the main blade (6) is arranged at the rear edge of the blade; a plurality of rudders (23) are evenly distributed on the same horizontal plane, and are vertically installed on the main reducer support frame (18), and the rudder (23) actuator is hinged to the outer edge of the fixed ring (21) through the ball bearing at the upper end; The annular cabin (1), the annular shell (2), the main hub (7), the main rotor shaft (8), the large spherical hinge core (9), the large spherical hinge ring (10), the moving ring (19), the main reducer (20) and the fixed ring (21) are coaxially arranged.

2. The helicopter rotor system according to claim 1, wherein The outer end of the torsion arm (4) is hinged to the outer edge of the moving ring (19) through the ball bearing; The outer end of the anti-torsion arm (22) is hinged to the outer edge of the fixed ring (21) through the ball bearing.

3. The helicopter rotor system of claim 1, wherein, The big ball hinge ring (10) is fixed with the fixed ring (21) through the tilt support rod (5), and the fixed ring (21) is hinged with the moving ring (19) through the big bearing (3).

4. The helicopter rotor system of claim 1, wherein, The big ball hinge core (9) is a hollow ball fixed outside a hollow column structure, the hollow column structure of the big ball hinge core (9) is sleeved on the main rotor shaft (8) and can slide up and down along the main rotor shaft (8); the hollow ball structure of the big ball hinge core (9) is wrapped in the big ball hinge ring (10) to form a spherical gap cooperation with the big ball hinge ring (10), the big ball hinge ring (10) can rotate around the hollow ball structure of the big ball hinge core (9) and also can push the big ball hinge core (9) to slide up and down along the main rotor shaft (8).

5. The helicopter rotor system of claim 1, wherein, The small pull rod (12) is a two-force rod structure, both ends of which are spherical bearings and the middle part is a solid rod.

6. The helicopter rotor system of claim 1, wherein, The main blade (6) is composed of inner and outer end horizontal shafts and a middle airfoil section; the inner end horizontal shaft of the main blade (6) is hinged on the outer edge of the main blade hub (7) through an elastic spherical bearing, and the outer end horizontal shaft of the main blade (6) is hinged on the upper end of the small pull rod (12) through an elastic spherical bearing.

7. The helicopter rotor system of claim 1, wherein, The steering engine (23) has three, When the actuating cylinders of the three steering engines (23) synchronously extend and retract by the same length, each small pull rod (12) pushes and pulls the corresponding main blade (6) to change the pitch by the same length, so that the total pitch is changed, the main rotor lift is uniformly increased or decreased, and the helicopter realizes the ascending or descending movement.

8. The helicopter rotor system according to claim 7, characterized in that, When the actuating cylinders of the three steering engines (23) extend and retract by different lengths respectively, each small pull rod (12) pushes and pulls the corresponding main blade (6) to change the pitch by different lengths, so that the periodic change of the pitch is realized, the main rotor lift is increased or decreased on a corresponding side, and the helicopter realizes the attitude movement of pitching and rolling.

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