Main rotor drive system of unmanned helicopter

Abstract

The present invention relates to an unmanned helicopter main rotor drive system, which includes a main reducer assembly, a rotor main shaft assembly and a mission platform assembly, wherein the main reducer assembly includes a gearbox, a driving gear, a driven gear, a driven gear mounting seat, an upper bearing, a lower bearing, a gearbox upper cover, a gearbox lower cover, an inner shaft tube fixing seat and a seal. The present invention designs a mission installation platform on the top of the rotor, and this position is particularly suitable for installing special devices such as satellite communication antennas and parachutes, which helps to expand the mission field of the helicopter and improve the mission load capacity. The present invention also integrates the rotor hub and the rotor shaft into one, thereby reducing the assembly workload, simplifying the assembly process, and improving the maintenance and repair efficiency. In addition, since the mechanical connection between the hub center piece and the rotor shaft is eliminated, the weight of the locally reinforced structure and the weight of the fasteners are reduced, the empty weight of the helicopter is reduced, and the mission capability of the helicopter is improved.

Description

Technical Field

[0001] The invention relates to a main rotor drive system for an unmanned helicopter and belongs to the field of mechanical structure design. Background Art

[0002] As the range of unmanned helicopters continues to increase, commonly used links can no longer meet the needs of long-distance communication. Satellite communication uses satellites as relays, which can meet the requirements of long-distance two-way transmission of images, flight control parameters, voice and other data between unmanned helicopters and control centers in a very large area, greatly expanding the control range and mission capabilities of unmanned helicopters. When using satellites as a means of communication, the basic requirement of no obstruction between the antenna and the satellite must be met. However, when unmanned helicopters fly in different directions in different postures on the surface of the earth, they are easily blocked by components such as the helicopter body, rotor hub, and automatic tilt device, interrupting the transmission of information. The top position of the center of the rotor hub is the highest position of the entire helicopter, which is an ideal position for installing a satellite communication antenna. Installing a satellite communication antenna here can ensure that the communication signal between the helicopter and the satellite is not blocked when the helicopter flies in almost all postures in any direction, and at the same time avoids interference with the signal by the swept rotor blades. Because signal transmission is directional, the satellite communication antenna must be pointed in the direction of the satellite. Although the satellite communication antenna itself is equipped with a direction adjustment mechanism, the installation platform is still required not to rotate quickly. Therefore, how to set a mission installation platform in the center of the rotor hub that does not rotate with the rotor has become a problem that needs to be solved urgently. Summary of the invention

[0003] The invention provides a rotor main shaft for an unmanned helicopter, which is used to solve the installation problem of a satellite communication antenna.

[0004] The technical solution of the present invention is realized in the following manner: a main rotor drive system of an unmanned helicopter, the system comprising a main reducer assembly, a rotor main shaft assembly and a task platform assembly, the main reducer assembly comprising a gearbox, a driving gear, a driven gear, a driven gear mounting seat, an upper bearing, a lower bearing, a gearbox upper cover, a gearbox lower cover, an inner shaft tube fixing seat and a seal, a step for supporting the upper bearing is arranged on the upper part of the gearbox, the driving gear is arranged on the side, a driven gear mounting seat is arranged at the center of the gearbox, the driven gear is arranged on the driven gear mounting seat, the gear mounting seat is positioned by the upper bearing and the lower bearing, a gearbox upper cover is arranged on the top of the gearbox, a gearbox lower cover is arranged on the bottom, the gearbox upper cover and the gearbox lower cover are fixedly connected to the gearbox by bolts, a step for supporting the lower bearing is arranged on the top surface of the gearbox lower cover, and an inner shaft tube fixing seat is arranged on the bottom surface of the gearbox lower cover;

[0005] The rotor main shaft assembly comprises a rotor main shaft and a fixing nut, the rotor main shaft comprises a hub center piece, a composite main shaft and a composite shaft, the top of the composite main shaft is sleeved on the bottom of the hub center piece, the bottom is sleeved on the top of the composite shaft, and the hub center piece and the composite shaft become an integral structure when the composite main shaft is cured, and the diameter of the rotor main shaft from the composite main shaft to the bottom composite shaft is not greater than the diameter of the upper section of the composite main shaft;

[0006] The task platform assembly comprises a task platform, a fairing, a top bearing and an inner shaft tube. The task platform is arranged on the top of the hub center piece. An insertion portion is arranged at the center of the lower side of the task platform. The insertion portion is hollow inside and has a step. The step is used to position the top bearing. The inner shaft tube is fixed to the bottom of the deep part of the task platform by screws. A fairing is also arranged on the task platform. The fairing wraps the top surface of the task platform and is used to rectify the equipment installed on the task platform and reduce air resistance.

[0007] A flange is arranged in the middle of the driven gear mounting seat, and positioning steps are arranged at the top and bottom of the driven gear mounting seat respectively. A driven gear is arranged at the lower side of the flange, and the positioning steps cooperate with the steps arranged in the gear box and on the upper part of the bottom surface of the gear box lower cover to clamp the upper bearing and the lower bearing. The driven gear mounting seat is a hollow cylinder with a middle part contracted inwardly, and an internal spline is arranged on the inner surface of the contracted part.

[0008] The hub center piece and the composite shaft are both metal parts. The bottom of the hub center piece and the top of the composite shaft are respectively sleeved in the composite material main shaft. A special treatment section is provided at the sleeve joint. The special treatment section includes a spike, a knurling treatment or a non-circular cross-sectional shape. The composite shaft is sequentially provided with a step, an upper cylindrical section, an external spline, and a lower cylindrical section from the special treatment section downward. The step, the upper cylindrical section, and the lower cylindrical section are all matched with the inner surface of the driven gear mounting seat. The external spline is matched with the internal spline of the driven gear mounting seat. An external thread is provided on the lower cylindrical section of the composite shaft.

[0009] The rotor main shaft is inserted into the main reducer assembly from top to bottom, the step of the composite shaft abuts against the top of the driven gear mounting seat, and the fixing nut is screwed in from the bottom of the composite shaft and tightly attached to the bottom of the driven gear mounting seat.

[0010] The rotor main shaft is hollow inside, and a step is set on the top of the hub center piece. The task platform assembly is inserted into the rotor main shaft from top to bottom. A top bearing is also set at the step of the hub center piece. The bottom of the inner shaft tube is fixed to the inner shaft tube fixing seat by screws.

[0011] A shaft tube is arranged at the center of the bottom of the task platform component. The shaft tube is inserted into the rotor main shaft, and the interior of the shaft tube is hollow.

[0012] The present invention designs a mission installation platform on the top of the rotor, which is particularly suitable for installing special devices such as satellite communication antennas and parachutes, which helps to expand the mission field of the helicopter and improve the mission load capacity, and has very important value. The present invention also integrates the rotor hub and the rotor shaft into one, thereby reducing the assembly workload, simplifying the assembly process, and improving the maintenance and repair efficiency. In addition, since the mechanical connection between the hub centerpiece and the rotor shaft is eliminated, the weight of the locally reinforced structure and the weight of the fasteners are reduced, the empty weight of the helicopter is reduced, and the mission capability of the helicopter is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the present invention;

[0014] Figure 2 It is a schematic diagram of the structure of the rotor main shaft assembly;

[0015] Figure 3 This is a schematic diagram of the task platform component structure;

[0016] Figure 4 Schematic diagram of the composite shaft structure.

[0017] Among them: 2-hub centerpiece, 3-composite main shaft, 4-composite shaft, 5-automatic tilter, 6-top bearing, 7-task platform, 8-inner shaft tube, 9-upper bearing, 10-lower bearing, 11-fastening nut, 12-first oil seal, 13-second oil seal, 14-third oil seal, 15-gearbox upper cover, 16-gearbox, 17-driven gear, 18-driven gear mounting seat, 19-gearbox lower cover, 20-inner shaft tube fixing seat, 21-driving gear, 22-spindle cover;

[0018] 4-1 Special treatment section, 4-2 Step, 4-3 Upper cylindrical section, 4-4 External spline, 4-5 Lower cylindrical section, 4-6 External thread. DETAILED DESCRIPTION

[0019] The present invention is described in further detail below:

[0020] The present embodiment provides a main rotor drive system for an unmanned helicopter, comprising a main reducer assembly, a rotor main shaft assembly and a mission platform assembly.

[0021] The main reducer assembly includes a gear box 16, a driving gear 21, a driven gear 17, a driven gear mounting seat 18, an upper bearing 9, a lower bearing 10, a gear box upper cover 15, a gear box lower cover 19, an inner shaft tube fixing seat 20 and a plurality of oil seals for sealing the lubricating oil in the main reducer.

[0022] The angle between the driving gear 21 and the driven gear 17 that drives the rotor main shaft to rotate is between 80° and 100°. The gear box 16 penetrates both sides of the rotor main shaft axially, and a step is provided in the top direction, allowing the upper bearing 9 to be installed and positioned from the inside upward, while the bottom direction has a larger opening, allowing the driven gear 17 and other components to be installed. It penetrates one side of the input shaft axially, and is used to install the driving gear 21 and the corresponding bearings, oil seals, end covers, etc. The driven gear mounting seat 18 is used to install the driven gear 17 and transmit the torque to the rotor main shaft at the same time. The gear box lower cover 19 is installed to the bottom of the gear box 16 by bolts, and a threaded blind hole is left at the bottom for installing the inner shaft tube fixing seat 20. A step is left at the center of its upper surface for positioning the outer ring of the lower bearing 10, and an oil seal is installed at the center penetration part.

[0023] During assembly, the upper bearing 9, the driven gear mounting seat 18, the driven gear 17, the lower bearing 10 and the gear box lower cover 19 can be assembled together first, then the gear box can be installed from the bottom and fixed with fasteners, and then the bottom oil seal, the inner shaft tube fixing seat 20, the top oil seal and the gear box upper cover 15, the driving gear 21 and the corresponding bearings, oil seals, end covers, etc. can be installed.

[0024] According to actual needs, the main reducer can have multiple driven gears to drive multiple devices to work.

[0025] The rotor main shaft comprises a rotor main shaft and a fixing nut, wherein the rotor main shaft comprises a hub center piece 2, a composite main shaft 3 and a composite shaft 4, and the composite main shaft 3 is sleeved on the bottom of the hub center piece 2 and the top 4 of the composite shaft before curing, and fixes the two together with itself during curing. The rotor main shaft from the bottom composite shaft 4 to the composite main shaft 3 has an outer diameter that is not larger than the part of the composite main shaft 3 near the top, so that the automatic tilt device can be inserted from the bottom and slide up and down on the composite main shaft 3 to control the rotor system pitch change.

[0026] The hub center piece 2 is made of metal, is hollow inside along the axial direction, has a step on the top for installing the bearing, and has a support arm circumferentially for installing the rotor blades. The outer surface of the axial bottom is specially treated to increase the interface bonding strength between the metal and the composite material. The special treatment forms include but are not limited to setting spikes, knurling, and using a non-circular cross-sectional shape.

[0027] The driven gear mounting seat 18 has a flange plate on its outside near the middle, and cylindrical surfaces at both ends. The flange plate and the cylindrical surfaces are provided with positioning steps respectively. The flange plate is used to install the driven gear 17. The steps on the cylindrical surfaces at both ends respectively position the inner rings of the upper bearing 9 and the lower bearing 10 with the gear box 16 and the gear box lower cover 19, and the outermost sections of the cylindrical surfaces on both sides are used to cooperate with the oil seal to achieve the sealing of the main reducer.

[0028] Specifically, the composite shaft 4 is made of metal, and the axial top is a special treatment section 4-1, which is specially treated to increase the interface strength between the metal and the composite material. Specifically, the special treatment section is in the shape of a spike, knurling or other non-circular cross-sectional shape, and a step 4-2 is arranged at the lower part of the special treatment section 4-1. When the rotor main shaft 1 is installed, the step 4-2 presses against the top end face of the driven gear mounting seat 18 from top to bottom, and limits the rotor main shaft 1 from axially not to move downward. The upper cylindrical section 4-3 arranged at the lower part of the step is aligned with the driven gear mounting seat 18. The upper end of the composite shaft 4 is radially positioned by the upper bearing 9 indirectly, and an external spline 4-4 is provided downwardly to transmit the torque to the rotor. A lower cylindrical section 4-5 is provided at the lower part of the external spline 4-4 to cooperate with the driven gear mounting seat 18, and radially position the lower end of the composite shaft 4 indirectly by the lower bearing 10. The lowest section of the composite shaft 4 is an external thread 4-6, and the locking nut 11 is screwed into the thread and simultaneously supports the bottom end face of the driven gear mounting seat, thereby finally realizing the axial and radial positioning of the rotor main shaft 1.

[0029] During assembly, first remove the inner shaft tube fixing seat from the main reducer assembly, insert the automatic tilt device into the rotor main shaft from one end of the composite shaft 4, and then insert the rotor main shaft into the main reducer assembly from top to bottom, then tighten the locking nut 11 and install the inner shaft tube fixing seat 20.

[0030] The main reducer of a common unmanned helicopter cannot be installed alone without a rotor main shaft, but the main reducer assembly designed in this scheme can be assembled and sealed independently without the rotor main shaft. The main reducer can be run-in alone, and there is no need to remove the main reducer from the fuselage or disassemble the main reducer when inspecting or replacing the rotor shaft of the helicopter, which greatly simplifies the maintenance process.

[0031] The mission platform assembly includes a mission platform 7, an inner shaft tube 8, a top bearing, and a fairing 22 for reducing resistance and protecting equipment. The mission platform assembly is inserted into the rotor main shaft from the top of the hub centerpiece 2, and is fixed to the inner shaft tube fixing seat 20 by screws, thereby ensuring that the mission platform 7 does not rotate, and the cables of the mission equipment can be led from the hollow interior of the inner shaft tube 8 to the fuselage. The mission platform 7 can be installed as needed, and installation or removal does not affect the operation of other equipment, and does not require any changes to the helicopter.

Claims

1. An unmanned helicopter main rotor drive system, characterized in that: The system comprises a main reducer assembly, a rotor main shaft assembly and a task platform assembly, wherein the main reducer assembly comprises a gearbox, a driving gear, a driven gear, a driven gear mounting seat, an upper bearing, a lower bearing, a gearbox upper cover, a gearbox lower cover, an inner shaft tube fixing seat and a seal, wherein a step for supporting the upper bearing is arranged on the upper part of the gearbox, the driving gear is arranged on the side, a driven gear mounting seat is arranged at the center of the gearbox, the driven gear is arranged on the driven gear mounting seat, the gear mounting seat is positioned by the upper bearing and the lower bearing, a gearbox upper cover is arranged on the top of the gearbox, a gearbox lower cover is arranged on the bottom, the gearbox upper cover and the gearbox lower cover are fixedly connected to the gearbox by bolts, a step for supporting the lower bearing is arranged on the top surface of the gearbox lower cover, and an inner shaft tube fixing seat is arranged on the bottom surface of the gearbox lower cover; The rotor main shaft assembly comprises a rotor main shaft and a fixing nut, the rotor main shaft comprises a hub center piece, a composite main shaft and a composite shaft, the top of the composite main shaft is sleeved on the bottom of the hub center piece, the bottom is sleeved on the top of the composite shaft, and the hub center piece and the composite shaft become an integral structure when the composite main shaft is cured, and the diameter of the rotor main shaft from the composite main shaft to the bottom composite shaft is not greater than the diameter of the upper section of the composite main shaft; The task platform assembly comprises a task platform, a fairing, a top bearing and an inner shaft tube. The task platform is arranged on the top of the hub center piece. An insertion portion is arranged at the center of the lower side of the task platform. The insertion portion is hollow inside and has a step. The step is used to position the top bearing. The inner shaft tube is fixed to the bottom of the deep part of the task platform by screws. A fairing is also arranged on the task platform. The fairing wraps the top surface of the task platform and is used to rectify the equipment installed on the task platform and reduce air resistance. A flange is arranged in the middle of the driven gear mounting seat, and positioning steps are arranged at the top and bottom of the driven gear mounting seat respectively. A driven gear is arranged at the lower side of the flange, and the positioning steps cooperate with the steps arranged in the gear box and on the upper part of the bottom surface of the gear box lower cover to clamp the upper bearing and the lower bearing. The driven gear mounting seat is a hollow cylinder with a middle part contracted inwardly, and an internal spline is arranged on the inner surface of the contracted part. The hub center piece and the composite shaft are both metal parts. The bottom of the hub center piece and the top of the composite shaft are respectively sleeved in the composite material main shaft, and a special treatment section is provided at the sleeve joint. The special treatment section includes setting spikes, knurling or designing a non-circular cross-sectional shape. The composite shaft is sequentially provided with a step, an upper cylindrical section, an external spline, and a lower cylindrical section from the special treatment section downward. The step, the upper cylindrical section, and the lower cylindrical section are all matched with the inner surface of the driven gear mounting seat. The external spline is matched with the internal spline of the driven gear mounting seat, and an external thread is provided on the lower cylindrical section of the composite shaft.

2. The unmanned helicopter main rotor drive system according to claim 1, characterized in that: The rotor main shaft is inserted into the main reducer assembly from top to bottom, the step of the composite shaft abuts against the top of the driven gear mounting seat, and the fixing nut is screwed in from the bottom of the composite shaft and tightly attached to the bottom of the driven gear mounting seat.

3. The unmanned helicopter main rotor drive system according to claim 1, characterized in that: The rotor main shaft is hollow inside, and a step is set on the top of the hub center piece. The task platform assembly is inserted into the rotor main shaft from top to bottom. A top bearing is also set at the step of the hub center piece. The bottom of the inner shaft tube is fixed to the inner shaft tube fixing seat by screws.

4. The unmanned helicopter main rotor drive system according to claim 1, characterized in that: A shaft tube is arranged at the center of the bottom of the task platform component. The shaft tube is inserted into the rotor main shaft, and the interior of the shaft tube is hollow.

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