阅读说明：本技术 小型共轴双旋翼式无人机 (Small coaxial double-rotor type unmanned aerial vehicle ) 是由 段瑞涵 唐云野 祖亚军 于 2019-08-30 设计创作，主要内容包括：本发明公开一种小型共轴双旋翼式无人机,其中,无人机包括：机体；上旋翼模块,包括彼此连接的上旋翼组件和上部电机；下旋翼模块,包括彼此连接的下旋翼组件和下部电机,其中,下旋翼组件包括下旋翼桨叶、用于安装下旋翼桨叶的下旋翼桨毂、用于安装下旋翼桨毂的下桨毂安装座、及用于改变上旋翼组件和下旋翼组件之间间距的单层变距机构,其中,单层变距机构一端连接到下旋翼桨毂,另一端以可转动方式连接到下桨毂安装座,其中,下部电机以可拆卸方式固定到空心主轴,且下桨毂安装座紧固到下部电机；以及倾斜盘模块,包括连接到下旋翼桨毂的倾斜盘拉杆。本发明通过提供单层变距机构,简化小型共轴双旋翼式无人机的结构,可靠性高。(The invention discloses a small coaxial double-rotor unmanned aerial vehicle, wherein the unmanned aerial vehicle comprises: a body; an upper rotor module including an upper rotor assembly and an upper motor connected to each other; a lower rotor module comprising a lower rotor assembly and a lower motor connected to each other, wherein the lower rotor assembly comprises a lower rotor blade, a lower rotor hub for mounting the lower rotor blade, a lower hub mount for mounting the lower rotor hub, and a single-layer pitch change mechanism for changing a spacing between the upper rotor assembly and the lower rotor assembly, wherein the single-layer pitch change mechanism has one end connected to the lower rotor hub and the other end rotatably connected to the lower hub mount, wherein the lower motor is detachably fixed to the hollow spindle, and the lower hub mount is fastened to the lower motor; and a swashplate module including a swashplate drawbar connected to the lower rotor hub. The invention simplifies the structure of the small coaxial double-rotor unmanned aerial vehicle by providing the single-layer pitch-varying mechanism, and has high reliability.)

1. A small coaxial dual rotor unmanned aerial vehicle, comprising:

the machine body comprises a shell and a hollow main shaft arranged in the shell;

an upper rotor module removably mounted to the hollow mast and comprising an upper rotor assembly and an upper motor connected to each other, wherein the upper rotor assembly comprises upper rotor blades and an upper rotor hub for mounting the upper rotor blades, wherein the upper motor is removably secured to the hollow mast and the upper rotor hub is secured to the upper motor;

a lower rotor module disposed below the upper rotor module and detachably mounted to the hollow mast, and including a lower rotor assembly and a lower motor connected to each other, wherein the lower rotor assembly includes a lower rotor blade, a lower rotor hub for mounting the lower rotor blade, a lower hub mount for mounting the lower rotor hub, and a single-layer pitch change mechanism for changing a space between the upper rotor assembly and the lower rotor assembly, wherein the single-layer pitch change mechanism has one end connected to the lower rotor hub and the other end rotatably connected to the lower hub mount, wherein the lower motor is detachably fixed to the hollow mast, and the lower hub mount is fastened to the lower motor; and

a swashplate module disposed below the lower rotor module and removably mounted to the hollow mast, and including a swashplate drawbar connected to the lower rotor hub.

2. A small coaxial twin rotor drone according to claim 1, characterised in that the single-layer pitch mechanism comprises a spacing shaft connected between the lower rotor hub and the lower hub mount in a direction parallel to the extension direction of the lower rotor blades, a through hole provided at the side of the lower rotor hub facing the lower hub mount, and opposed spacing holes provided at the side of the lower hub mount facing the through hole, wherein one end of the spacing shaft is fastened to the through hole and the other end is rotatably mounted in the spacing holes, so that the lower rotor hub realizes the pitch action by the axial rotation of the spacing shaft in the spacing holes.

3. A small co-axial twin rotor drone according to claim 1, characterised in that the upper motor comprises an upper rotor and an upper stator used in cooperation, wherein the upper rotor is rotatable with respect to the upper stator, wherein the upper rotor hub is fastened to the upper rotor and the upper stator is fixed in a removable way to the hollow main shaft.

4. A small coaxial twin rotor drone according to claim 1, wherein the lower motor comprises a lower rotor and a lower stator used in concert, wherein the lower rotor is rotatable relative to the lower stator, wherein the lower hub mount is secured to the lower rotor, and wherein the lower stator is removably secured to the hollow main shaft.

5. A small co-axial twin rotor drone according to claim 1, characterised in that the swashplate module is mounted to the hollow main shaft by means of a bearing connection, so that the swashplate module can tilt relative to the hollow main shaft.

6. A small coaxial twin rotor drone according to claim 5, characterised in that the swashplate module further comprises:

a swash plate bearing groove tightly fitted to the hollow main shaft;

a rolling bearing assembly mounted in the tilt disk bearing groove, including a rolling bearing; and

the fisheye bearing assembly is in tight fit with the rolling bearing assembly, wherein the fisheye bearing assembly comprises a fisheye bearing, a fisheye bearing seat used for installing the fisheye bearing, and a first metal ball head detachably connected to the fisheye bearing seat, and the rolling bearing and the fisheye bearing seat are in interference fit together.

7. A small coaxial twin rotor drone according to claim 6, characterised in that the swashplate module comprises at least one swashplate drawbar connected to the swashplate bearing slot by a shaft hole fit at one end and to the lower rotor hub by a shaft hole fit at the other end.

8. A small coaxial twin rotor drone according to claim 6, further comprising a steering engine module mounted in a removable manner to the hollow main shaft, disposed below the swashplate module and comprising:

two steering engines;

one end of each steering engine rocker arm is connected to the corresponding steering engine in a swinging mode, and the other end of each steering engine rocker arm is provided with a second metal ball head;

one end of each steering engine connecting rod is connected to a first metal ball head of the tilting disk module, and the other end of each steering engine connecting rod is sleeved on a second metal ball head of the corresponding steering engine rocker arm;

the steering engine bin is used for accommodating a steering engine, a steering engine rocker arm and a steering engine connecting rod;

and the steering engine bin mounting table is used for mounting a steering engine and a steering engine bin and is detachably fixed to the hollow main shaft.

9. A small co-axial dual rotor drone according to claim 1, characterised in that the upper and lower rotor blades are rigid blades with high lift-to-drag ratio.

10. A small coaxial twin rotor drone according to claim 1, characterized in that it is a modular drone.

Technical Field

The invention relates to the technical field of aircrafts, in particular to a small coaxial double-rotor unmanned aerial vehicle.

Background

The development of unmanned aerial vehicles has been 80 years old so far. A drone is an unmanned aircraft that is operated by a radio remote control device and a self-contained program control device. The machine has no cockpit, but is provided with an automatic pilot, a program control device and other equipment. Personnel on the ground, a naval vessel or a mother aircraft remote control station track, position, remotely control, telemeter and digitally transmit the unmanned aerial vehicle through equipment such as a radar. The unmanned aerial vehicle can take off like a common airplane or launch by a boosting rocket under the radio remote control, and can also be thrown into the air by the mother aircraft for flying. During recovery, the unmanned aerial vehicle can automatically land in the same way as a common aircraft in the landing process, and can also be recovered by a parachute or a barrier net through remote control. Unmanned aerial vehicle can use many times repeatedly.

Unmanned aerial vehicles can be classified into military and civil according to application fields. For military use, unmanned aerial vehicles can be widely used for aerial reconnaissance, monitoring, communication, anti-submergence, electronic interference and the like. In the civil aspect, the system can be widely applied to the fields of aerial photography, agriculture, plant protection, miniature self-timer, express transportation, disaster relief, wild animal observation, infectious disease monitoring, surveying and mapping, news reporting, power inspection, disaster relief, movie and television shooting and the like. By scale classification (civil aviation regulations), unmanned aerial vehicles can be divided into micro unmanned aerial vehicles, light unmanned aerial vehicles, small unmanned aerial vehicles and large unmanned aerial vehicles. The mass of the micro unmanned aerial vehicle is less than or equal to 7 kg. The light unmanned aerial vehicle is an unmanned aerial vehicle with the mass larger than 7kg but smaller than or equal to 116kg, and the corrected airspeed is smaller than 100km/h (55nmile/h) and the lift limit is smaller than 3000m in full-horsepower flat flight. The small unmanned aerial vehicle is an unmanned aerial vehicle with the mass of the air aircraft less than or equal to 5700kg, except for micro and light unmanned aerial vehicles. Large-scale unmanned aerial vehicle is that the empty quick-witted quality is greater than 5700 kg.

The traditional single-rotor unmanned helicopter needs to balance reaction torque and control course, so that a tail rotor is required to be configured, the structure is complex, the size is large, the reliability is poor, and the tail rotor consumes 30% of power.

The existing micro unmanned aerial vehicle is mainly applied to military purposes, so that higher requirements are provided for the stability of task loads such as monitoring equipment and monitoring equipment carried by the micro unmanned aerial vehicle. However, with the miniaturization development of the micro unmanned aerial vehicle, the whole weight is lighter and lighter, the vibration of the fuselage can be more obvious, and the stability of the task load operation can be influenced sometimes. Meanwhile, under some special conditions, due to the requirements of different tasks, different requirements are often met on the performance of the micro unmanned aerial vehicle, but the micro unmanned aerial vehicle is often strong in integrity and poor in compatibility, and when the tasks are executed, a plurality of or multiple groups of micro unmanned aerial vehicles executing different tasks are often required to be carried, so that the cost of executing the tasks is increased, and the maintenance is not facilitated.

The coaxial double-rotor helicopter is characterized by that it has two pairs of upper and lower rotors, i.e. upper rotor and lower rotor, which are rotated around same theoretical axis in forward and backward directions, and two pairs of rotors are identical, and they are mounted on same rotor shaft one above the other and one below the other, and between two pairs of rotors a certain distance is set. The two rotors rotate in opposite directions, so that their reaction torques can cancel each other out. The existing coaxial dual-rotor unmanned aerial vehicle is mostly connected with mechanisms such as a speed reducer, two output shafts which turn reversely through the speed reducer are respectively connected with an upper rotor and a lower rotor so as to realize the reverse rotation of the upper rotor and the lower rotor, and therefore the reaction torque brought by the two rotors is mutually offset. Thus, the coaxial dual-rotor helicopter does not need to be provided with a tail rotor. Generally, the heading control of the coaxial dual-rotor helicopter is completed by means of differential change of the collective pitch of the upper rotor and the lower rotor.

The coaxial dual-rotor helicopter has the main advantages of compact structure and small overall dimension, and can greatly shorten the length of a helicopter body because a long tail beam does not need to be installed without a tail rotor, thereby realizing miniaturization. Further, the coaxial twin-rotor helicopter has two pairs of rotors generating lift force, and the diameter of each rotor can be shortened. In addition, the body components can be compactly arranged at the center of gravity of the helicopter, so that the flight stability is good and the operation is convenient. Compared with a single-rotor helicopter with a tail rotor, the helicopter has the advantage that the operation efficiency is obviously improved.

In addition, but coaxial two rotor unmanned aerial vehicle's advantage still includes VTOL, and aerodynamic force is symmetrical, and efficiency ratio of hovering is higher, requires lowly and uses convenient etc. to the take off and land place, therefore development prospect is huge.

At present, a coaxial unmanned aerial vehicle can be divided into a traditional mechanical coaxial type and an electric control coaxial type, the traditional mechanical coaxial type can be controlled by a plurality of mechanical connecting rods, for example, a Russian card type helicopter is provided, and the electric control system of the steering engine can be provided with the electric control system of 6 steering engines at present, so that the mechanical structure is reduced, and the reliability is improved. However, both of the above-mentioned coaxial drones are controlled by the upper and lower full pitch of the blades of the upper and lower rotors. Although mechanical structure has been simplified for traditional mechanical type coaxial type, automatically controlled coaxial type, still use 6 steering wheel double-inclined plate control, steering wheel quantity is more, and the steering wheel then has the risk of falling into the air if breaking down.

Therefore, the existing coaxial dual-rotor unmanned aerial vehicle mostly adopts the full-variable-pitch operation of the upper and lower blades so as to change the flight state of the unmanned aerial vehicle. Consequently, lead to above-mentioned unmanned aerial vehicle structure complicacy, difficult maintenance, the reliability is low.

The motor is unmanned aerial vehicle's power core part, but, current unmanned aerial vehicle motor is not only bulky, heavy, and power is little moreover, and the moment of torsion is little, and the bearing capacity is low, and duration is short, seriously restricts unmanned aerial vehicle's development, can not satisfy coaxial two rotor unmanned aerial vehicle's requirement.

There is therefore a need in the art for a new small coaxial twin rotor drone that eliminates or at least alleviates some or all of the above-mentioned drawbacks of the coaxial twin rotor drones of the prior art.

Disclosure of Invention

In view of the above technical problems in the prior art, an object of the present invention is to provide a small coaxial dual-rotor unmanned aerial vehicle, which simplifies the structure of the small coaxial dual-rotor unmanned aerial vehicle by providing a single-layer pitch varying mechanism, and has high reliability. Furthermore, the invention can simplify the complex transmission problem of the small coaxial double-rotor type unmanned aerial vehicle by a direct drive mode of the motor. Furthermore, the invention can reduce the mechanical structure and further improve the reliability by providing the 2-steering engine electric control system. In addition, the invention can also provide the blade with high lift-drag ratio to improve the efficiency of the blade.

To this end, the present invention discloses a small-sized coaxial dual-rotor type unmanned aerial vehicle according to an embodiment of the present invention, wherein the unmanned aerial vehicle includes:

the machine body comprises a shell and a hollow main shaft arranged in the shell;

an upper rotor module removably mounted to the hollow mast and comprising an upper rotor assembly and an upper motor connected to each other, wherein the upper rotor assembly comprises upper rotor blades and an upper rotor hub for mounting the upper rotor blades, wherein the upper motor is removably secured to the hollow mast and the upper rotor hub is secured to the upper motor;

a lower rotor module disposed below the upper rotor module and detachably mounted to the hollow mast, and including a lower rotor assembly and a lower motor connected to each other, wherein the lower rotor assembly includes a lower rotor blade, a lower rotor hub for mounting the lower rotor blade, a lower hub mount for mounting the lower rotor hub, and a single-layer pitch change mechanism for changing a space between the upper rotor assembly and the lower rotor assembly, wherein the single-layer pitch change mechanism has one end connected to the lower rotor hub and the other end rotatably connected to the lower hub mount, wherein the lower motor is detachably fixed to the hollow mast, and the lower hub mount is fastened to the lower motor; and

a swashplate module disposed below the lower rotor module and removably mounted to the hollow mast, and including a swashplate drawbar connected to the lower rotor hub.

In one embodiment, the single-layer pitch mechanism may include a spacing shaft connected between the lower rotor hub and the lower hub mount in a direction parallel to the extension direction of the lower rotor blade, a through hole provided at a side of the lower rotor hub facing the lower hub mount, and opposing spacing holes provided at a side of the lower hub mount facing the through hole, wherein the spacing shaft may have one end fastened to the through hole and the other end rotatably mounted in the spacing holes such that the lower rotor hub may achieve a pitch action by axial rotation of the spacing shaft in the spacing holes.

In one embodiment, the upper motor may include an upper rotor and an upper stator configured for use, wherein the upper rotor is rotatable relative to the upper stator, wherein the upper rotor hub may be secured to the upper rotor and the upper stator may be removably secured to the hollow spindle.

In one embodiment, the lower motor may comprise a lower rotor and a lower stator used in cooperation, wherein the lower rotor is rotatable relative to the lower stator, wherein the lower hub mount may be fastened to the lower rotor and the lower stator may be detachably secured to the hollow main shaft.

In an embodiment, the swashplate module may be mounted to the hollow main shaft by a bearing connection, such that the swashplate module is able to tilt relative to the hollow main shaft.

In an embodiment, the swashplate module may further include:

a swash plate bearing groove tightly fitted to the hollow main shaft;

a rolling bearing assembly mounted in the tilt disk bearing groove, including a rolling bearing; and

the fisheye bearing assembly is tightly matched with the rolling bearing assembly, wherein the fisheye bearing assembly can comprise a fisheye bearing, a fisheye bearing seat used for installing the fisheye bearing and a first metal ball head detachably connected to the fisheye bearing seat, and the rolling bearing can be in interference fit with the fisheye bearing seat.

In an embodiment, the swashplate module may include at least one swashplate drawbar, which may be coupled to the swashplate bearing slot at one end and to the lower rotor hub at the other end by a shaft-hole fit.

In an embodiment, the above small coaxial dual-rotor type drone may further include a steering engine module detachably mounted to the hollow main shaft, disposed below the swashplate module, and including:

two steering engines;

one end of each steering engine rocker arm is connected to the corresponding steering engine in a swinging mode, and the other end of each steering engine rocker arm is provided with a second metal ball head;

one end of each steering engine connecting rod is connected to a first metal ball head of the tilting disk module, and the other end of each steering engine connecting rod is sleeved on a second metal ball head of the corresponding steering engine rocker arm;

the steering engine bin is used for accommodating a steering engine, a steering engine rocker arm and a steering engine connecting rod;

and the steering engine bin mounting table is used for mounting a steering engine and a steering engine bin and is detachably fixed to the hollow main shaft.

In an embodiment, the upper and lower rotor blades may each be rigid blades having a high lift-to-drag ratio.

In an embodiment, the small coaxial dual-rotor unmanned aerial vehicle can be a modular unmanned aerial vehicle.

The small coaxial double-rotor unmanned aerial vehicle provided by the embodiment of the invention has the following beneficial effects:

by providing a single-layer pitch mechanism only at the lower rotor module, the complex structure of an existing full-pitch coaxial helicopter can be simplified, making the structure more compact.

Furthermore, the invention can eliminate the defects of high integration degree, difficult external mounting and inconvenient load selection of the existing helicopter by providing a modular design.

Furthermore, the invention can improve the efficiency of the blades and eliminate the defect that the blades are easy to beat by adopting the high-lift-drag-ratio constant-pitch blades.

Furthermore, the motor direct drive design is provided, so that the transmission structure can be reduced, the structure is further simplified, the structure is more compact, and the reliability is improved.

Furthermore, the unmanned aerial vehicle is controlled by only two steering engines, so that the number of the steering engines can be reduced, the reliability is greatly improved, and the failure rate is greatly reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

figure 1 schematically illustrates a front view of a small coaxial dual rotor drone according to an embodiment of the invention;

figure 2 schematically shows a side view of the small coaxial dual rotor drone of figure 1;

figure 3 schematically illustrates an exploded perspective view of the small coaxial dual rotor drone of figure 1;

figure 4 schematically illustrates a front view of the small coaxial dual rotor drone of figure 1 with a partial casing removed;

figure 5 schematically shows a side view of the small coaxial dual rotor drone of figure 4;

figure 6 schematically shows a perspective view of the small coaxial dual rotor drone of figure 4;

figure 7 schematically illustrates a partial view a of the small coaxial dual rotor drone of figure 6, mainly showing a single layer pitch mechanism;

figure 8 schematically illustrates a partial cross-sectional view of an upper rotor hub with an upper rotor blade grip of the small co-axial twin-rotor drone of figure 4 in an extended state and a folded state, and a perspective view in a folded state, respectively;

figure 9 schematically illustrates a perspective view of the small coaxial dual rotor drone of figure 1 with the upper and lower rotor blades in a folded condition;

figure 10 schematically illustrates a partial view B of the small coaxial dual rotor drone of figure 6;

figure 11 schematically illustrates an exploded view of the swashplate module of the small coaxial dual rotor drone of figure 4;

figure 12 schematically illustrates various state diagrams of the landing gear of the small coaxial dual rotor drone of figure 1.

Description of the reference numerals

100: an unmanned aerial vehicle; 110: a body; 111: a housing; 112: a hollow main shaft; 120: an upper rotor module; 121: an upper rotor assembly; 122: an upper rotor blade; 123: an upper rotor hub; 124: an upper motor; 125: an upper rotor blade clamp; 130: a lower rotor module; 131: a lower rotor assembly; 132: a lower rotor blade; 133: a lower rotor hub; 134: a lower hub mount; 135: a lower motor; 136: a limiting shaft; 137: a through hole; 138: a limiting hole; 140: a tilt tray module; 141: a swashplate drawbar; 142: a swash plate bearing groove; 143: a rolling bearing; 144: a fisheye bearing assembly; 145: a fisheye bearing; 146: a fisheye bearing seat; 147: a first metal ball head; 150: a steering engine module; 151: a steering engine; 152: a steering engine rocker arm; 153: a second metal ball head; 154: a steering engine connecting rod; 160: a navigation module; 170: a flight control module; 180: a power supply module; 190: a landing gear.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

The technical scheme provided by the embodiment of the invention is described in detail below with reference to the accompanying drawings.

Referring to fig. 1 to 7 and 10, a small coaxial twin rotor drone 100 according to an embodiment of the invention is shown, wherein the drone 100 comprises:

a body 110 including a housing 111 and a hollow main shaft 112 installed inside the housing 111;

an upper rotor module 120 removably mounted to the hollow mast 112 and including an upper rotor assembly 121 and an upper motor 124 connected to each other, wherein the upper rotor assembly 121 includes upper rotor blades 122 and an upper rotor hub 123 for mounting the upper rotor blades 122, wherein the upper motor 124 is removably secured to the hollow mast 112 and the upper rotor hub 123 is secured to the upper motor 124;

a lower rotor module 130 disposed below upper rotor module 120 and removably mounted to hollow mast 112, and including a lower rotor assembly 131 and a lower motor 135 connected to each other, wherein lower rotor assembly 131 includes lower rotor blades 132, a lower rotor hub 133 for mounting lower rotor blades 132, a lower hub mount 134 for mounting lower rotor hub 133, and a single-deck pitch mechanism for varying a spacing between upper rotor assembly 121 and lower rotor assembly 131, wherein the single-deck pitch mechanism has one end connected to lower rotor hub 133 and the other end rotatably connected to lower hub mount 134, wherein lower motor 135 is removably secured to hollow mast 112 and lower hub mount 134 is secured to lower motor 135; and

a swashplate module 140, which is disposed below the lower rotor module 130 and is removably mounted to the hollow mast 112, and includes swashplate tie rods 141 connected to the lower rotor hub 133.

Referring to fig. 7, in an embodiment, the single-layer pitch mechanism may include a spacing shaft 136 connected between the lower rotor hub 133 and the lower hub mount 134 in a direction parallel to the extending direction of the lower rotor blades 132, a through hole 137 provided at a side of the lower rotor hub 133 facing the lower hub mount 134, and an opposite spacing hole 138 provided at a side of the lower hub mount 134 facing the through hole 137, wherein the spacing shaft 136 may have one end fastened to the through hole 137 and the other end rotatably mounted in the spacing hole 138, such that the lower rotor hub 133 may perform a pitch action by axial rotation of the spacing shaft 136 in the spacing hole 138.

In one embodiment, upper rotor blades 122 may be mounted to upper rotor hub 123 via upper rotor blade grips 125, and lower rotor blades 132 may be mounted to lower rotor hub 133 via lower rotor blade grips.

For example, the upper rotor blade 122 and the upper rotor blade clamp 125 may be coupled by a threaded connection such as a bolt, and the upper rotor blade clamp 125 may be assembled to the upper rotor hub 123 by a threaded connection such as a bolt-and-nut fit, and after installation, the upper rotor blade 122 may be folded up and down about the bolt axis, and the upper rotor blade clamp 125 may also be folded up and down about the bolt axis. Fig. 8 (a), (b), and (c) show schematic views of upper rotor blade grip 125 in an extended state and a collapsed state, respectively, and perspective views in the collapsed state.

In an embodiment, upper rotor module 120 may also include an upper hub mount for mounting upper rotor hub 123, but does not include a pitch mechanism.

Similarly, the lower rotor blade 132 and the lower rotor blade clamp may be connected by a threaded connection such as a bolt, and the lower rotor blade clamp may be assembled to the lower rotor hub 133 by a threaded connection such as a bolt-nut fit, and after the assembly is completed, the lower rotor blade 132 may be folded up and down about the bolt axis, and the lower rotor blade clamp may be folded up and down about the bolt axis.

Figure 9 schematically illustrates a perspective view of the small coaxial dual rotor drone of figure 1 with the upper and lower rotor blades in a folded state.

In one embodiment, the upper motor 124 may include a mating upper rotor and upper stator, wherein the upper rotor is rotatable relative to the upper stator, wherein the upper rotor hub 123 may be secured to the upper rotor and the upper stator may be removably secured to the hollow main shaft 112. Typically, the upper motor 124 may be a brushless motor. For example, the upper rotor hub 123 may be securely fitted to the upper rotor of the upper motor 124 by a connection means such as a screw, and the upper stator may be fixed to the hollow main shaft 112 by means of a bolt or the like and through a locating hole set of the upper stator. The upper stator and the upper rotor can axially rotate. The wiring harness of the upper motor 124 may pass through the hollow main shaft 112.

In one embodiment, the lower motor 135 may include a lower rotor and a lower stator that are used in concert, wherein the lower rotor is rotatable relative to the lower stator, wherein the lower hub mount 134 may be secured to the lower rotor and the lower stator may be removably secured to the hollow main shaft 112. Typically, the lower motor 135 may also be a brushless motor. The lower stator may be fixed to the hollow main shaft 112 by means of bolts or the like, and through positioning holes of the lower stator. The lower hub mount 134 may be securely fitted to the lower rotor by a threaded connection such as a screw. Lower rotor hub 133 may be mounted to lower hub mount 134, for example, via a single-layer pitch mechanism such as a spacer shaft 136, such that lower rotor hub 133 may be rotated axially by spacer shaft 136 to vary the spacing between upper rotor assembly 121 and lower rotor assembly 131 to achieve a pitch change action.

Therefore, the small coaxial double-rotor unmanned aerial vehicle is in a motor direct-drive type.

Further, to control the lower rotor hub 133 to perform a pitch change action, the lower rotor hub 133 may be connected to the swashplate drawbar 141 of the swashplate module 140, as shown in fig. 5 and 10.

In one embodiment, the swashplate module 140 may be mounted to the hollow main shaft 112 via a bearing connection such that the swashplate module 140 may tilt or rotate relative to the hollow main shaft 112, as shown in FIG. 11.

Referring to fig. 10 and 11, in an embodiment, the swashplate module 140 may include: a tilt disk bearing groove 142 tightly fitted to the hollow main shaft 112; a rolling bearing assembly, which may include a rolling bearing 143, mounted into the swashplate bearing groove 142; and a fisheye bearing assembly 144 in tight fit with the rolling bearing assembly, wherein the fisheye bearing assembly 144 may include a fisheye bearing 145, a fisheye bearing seat 146 for mounting the fisheye bearing 145, and a first metal ball head 147 detachably connected to the fisheye bearing seat 146, wherein the rolling bearing 143 may be interference fitted with the fisheye bearing seat 146. In addition, the tilting disk module 140 can be connected with a ball-head pull rod to connect with the steering engine module 150 below.

In one embodiment, the swashplate module 140 may also include at least one swashplate drawbar 141 coupled at one end to the swashplate bearing slot via a shaft-hole fit and at the other end to the lower rotor hub 133 via a shaft-hole fit.

For example, in one embodiment, swashplate module 140 may include a swashplate drawbar 141 coupled at one end to the swashplate bearing slot via a shaft-in-hole fit and at the other end to lower rotor hub 133 via a shaft-in-hole fit.

In an alternative embodiment, the swashplate module 140 may include two swashplate tie rods 141 symmetrically disposed on either side of the hollow main shaft 112, one end of which is coupled to the swashplate bearing slot by a shaft-in-hole fit and the other end of which is coupled to the lower rotor hub 133 by a shaft-in-hole fit.

As shown in fig. 10, in one embodiment, the drone 100 may further include a steering engine module 150 removably mounted to the hollow main shaft 112, which may be disposed below the swashplate module 140, and which includes:

two steering engines 151;

two steering engine rocker arms 152, wherein one end of each steering engine rocker arm 152 is connected to the corresponding steering engine 151 in a swinging mode, and the other end of each steering engine rocker arm 152 is provided with a second metal ball head 153;

two steering engine connecting rods 154, wherein one end of each steering engine connecting rod 154 is connected to the first metal ball head 147 of the tilting tray module 140, and the other end is sleeved on the second metal ball head 153 of the corresponding steering engine rocker arm 152;

the steering engine bin is used for accommodating a steering engine 151, a steering engine rocker arm 152 and a steering engine connecting rod 154;

and the steering engine bin mounting table is used for mounting the steering engine 151 and the steering engine bin and is detachably fixed to the hollow main shaft 112.

In one embodiment, each steering engine rocker arm may be a ball-end link, one end of which is sleeved to the first metal ball 147.

In an embodiment, the steering engine rocker arm 152 may be connected to the steering engine 151 through a screw connection manner, such as a screw, the second metal ball 153 may be mounted on the steering engine rocker arm 152 for mounting a ball pull rod, the steering engine 151 may be mounted on the steering engine compartment mounting table through a connection member, such as a bolt, the ball pull rod is sleeved on or fastened to the second metal ball 153 and connected to the tilt tray module 140 upward, and the tilt tray module 140 is controlled by the swing of the steering engine rocker arm 151.

In an embodiment, the upper rotor blade 122 and the lower rotor blade 132 may each be a rigid blade. Further, the upper and lower rotor blades 122, 132 may each be a rigid blade having a high lift-to-drag ratio. The ratio of lift force to resistance force when the unmanned aerial vehicle flies is called lift-drag ratio for short.

In an embodiment, the drone 100 may also include a navigation module 160 disposed on top of the drone 100, above the upper rotor module 120, and removably connected to the hollow main shaft 112, as shown in fig. 1 and 4. The navigation module 160 may be, for example, a GPS navigation module. Navigation module 160 may be connected to the flight controls in flight control module 170 through hollow main shaft 112.

As shown in fig. 4, in an embodiment, the drone 100 may further include a flight control module 170 disposed below the steering engine module 150 and detachably connected to the steering engine module 150, and including: the flight control cabin is detachably connected to the rudder cabin; and the flight control device is detachably accommodated in the flight control cabin.

In an embodiment, the drone 100 may also include electronic governors for the upper motor 124 and the lower motor 135, which are mounted within the flight control bay and located on either side of the flight control.

In one embodiment, the flight control can be mounted in the flight control cabin by means of damping double-sided adhesive, the electronic speed regulator can be mounted on two sides of the flight control, and radiating fins for radiating heat can be arranged on the electronic speed regulator. The flight control cabin can be connected with the steering engine cabin through a flange.

As shown in fig. 4, in an embodiment, the drone 100 may further include a power module 180 for being disposed below the flight control module, including: the battery cabin is detachably connected to the flight control cabin; and the battery is accommodated in the battery bin. For example, the battery compartment may be flanged to the flight control compartment.

In an embodiment, the drone 100 may also include a landing gear 190 removably disposed on the bottom of the drone 100, which is foldable relative to the drone 100, as shown in fig. 4 and 12. Fig. 12 (d), (e) and (f) schematically show a fully extended view, a support state view and a folded state view of the landing gear 190 of the small coaxial double rotor drone of fig. 1, respectively.

As shown in fig. 4 and 12, the drone 100 may be provided with landing gear 190 at the bottom, and the drone 100 may be provided with mounting brackets for the landing gear 190 at the bottom when the various load modules are installed. The mounting bracket may be connected to the bottom of the drone 100 by connectors such as bolts. For example, the landing gear 190 may be provided with 4 support feet to ensure support for the drone 100 when taking off and landing. The support feet of the landing gear 190 may be mounted to the mounting bracket by connectors, such as bolts, and may be folded about an axis so that the landing gear 190 may be folded onto the body 110 when carried.

In one embodiment, the housing 111 may be mounted to the body 110 by a connector, such as a bolt, to provide a barrier between the compartments, and to prevent dust and water.

As described above, the small coaxial dual-rotor drone 100 of the present invention may be a modular drone.

In comparison, most of the existing helicopters are single-rotor helicopters with tail rotors, and the tail rotors of the helicopters consume 30%. Coaxial helicopters, represented by the bayonet system, have then emerged. However, the problems of complex mechanical structure, poor reliability and easy oar beating of the upper and lower paddles during high maneuvering action are not widely popularized, and then the second generation electric control coaxial solves the maintenance problem of complex mechanical connecting rods and simplifies the control structure. But the failure rate is still high due to problems of blade stiffness and steering engine reliability.

The invention reduces the transmission structure and improves the reliability by using the design of direct drive of the motor, avoids the risk of oar beating of two layers of paddles by using the rigid paddle, controls the airplane by two steering engines, reduces 4 control steering engines compared with the second generation electric control coaxial, and greatly improves the reliability.

The blades of the unmanned aerial vehicle adopt the high lift-drag ratio constant-pitch blades, the aircraft does not change lift force by total distance control, the aircraft is controlled to ascend and descend by the rotating speed of the motor, the tilting tray module can control the unmanned aerial vehicle to pitch and roll by controlling the periodic variable distance of the unmanned aerial vehicle through the two steering engines, and the steering of the motor is realized by unbalanced moment generated by the differential speed of the upper motor and the lower motor.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. In addition, "front", "rear", "left", "right", "upper" and "lower" in this document are referred to the placement states shown in the drawings.

Finally, it should be noted that: the above examples are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.