CN109987222B

CN109987222B - Unmanned aerial vehicle, power transmission system and method for reducing air resistance in unmanned aerial vehicle

Info

Publication number: CN109987222B
Application number: CN201810001442.6A
Authority: CN
Inventors: 田瑜
Original assignee: Shanghai Autoflight Co Ltd
Current assignee: Shanghai Autoflight Co Ltd
Priority date: 2018-01-02
Filing date: 2018-01-02
Publication date: 2022-06-24
Anticipated expiration: 2038-01-02
Also published as: CN109987222A; WO2019134356A1

Abstract

A drone, a power train and a method of reducing air resistance in a drone, wherein a motor is arranged within a support arm or within a wing such that the motor shaft is parallel to the longitudinal axis of the support arm or wing. There is a connector arranged to transmit torque from the motor shaft to a propeller of the drone. The problem of the aerodynamic profile and the air resistance of current aircraft are big is solved, a light motor for unmanned aircraft and a use thereof are provided.

Description

Unmanned aerial vehicle, power train and method for reducing air resistance in unmanned aerial vehicle

Technical Field

The present invention relates to a structure of a lightweight motor, and more particularly, to a lightweight motor for an unmanned aerial vehicle (unmanned aerial vehicle, i.e., UAV) and an unmanned aerial vehicle having the same. Although the present invention is applicable to any drone or aircraft, it is particularly applicable to fixed wing drones and Vertical Take Off and Landing (VTOL) multi-rotor drones because these drones have a low profile and aerodynamic design that minimizes drag during flight.

Background

Generally, an unmanned aircraft is an Unmanned Aerial Vehicle (UAV) piloted by a user for remote or autonomous flight. Unmanned aircraft are known to perform various functions in military applications and civilian applications. In particular, unmanned aircraft may undertake payload, capture images or video, data gathering and environmental investigation. Some unmanned aircraft are considered as fixed-wing unmanned aircraft, and generally have longer flight time and faster flight speed. There are also drones known as vertical take-off and landing (VTOL) multi-rotor drones, which generally have slower flight speeds when compared to fixed wing drones.

The related art VTOL multi-rotor drone is composed of a body and a plurality of propellers, all driven by a motor. The number of propellers is typically a double number, for example four, six or eight. The motors are supported on radially extending support arms. The VTOL multi-rotor drone has a plurality of propellers each having a plane of rotation substantially parallel to the ground, allowing the VTOL drone to take off and land vertically.

Related art fixed wing unmanned aircraft typically have a fuselage, a pair of wings, and a pair of horizontal stabilizers. Conventional fixed wing unmanned aircraft use runways to take off and land. However, fixed wing drones are also known to have propellers each having a plane of rotation substantially parallel to the ground, allowing the fixed wing drone to take off and land vertically similar to a VTOL multi-rotor drone.

Whether it is a VTOL multi-rotor drone or a fixed-wing drone with vertical take-off and landing capability, the propellers in these drones are driven by motors. Each motor is configured to drive one propeller. Each motor is placed in a motor housing.

Recently, VTOL multi-rotor drone designed for civilian use equipped with four, six or eight propellers has been widely used. In these drones, the motor driving each propeller is located directly below each propeller in a conspicuous motor housing.

There is a continuing need for new methods of designing the aerodynamics of VTOL multi-rotor drones and fixed-wing drones.

All referenced patents, applications, and documents are incorporated by reference herein in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. The disclosed embodiments may seek to meet one or more of the above-mentioned desires. While the present embodiments may obviate one or more of the above-described needs, it will be appreciated that aspects of the embodiments may not necessarily obviate their need.

Disclosure of Invention

The invention provides a light motor for an unmanned aircraft and a use method thereof, aiming at solving the problems of large aerodynamic profile and air resistance of the existing aircraft.

An Unmanned Aerial Vehicle (UAV) having at least one motor, each motor having a motor shaft; at least one propeller, each propeller having a propeller axis, wherein each propeller is driven by a motor. The propeller shaft may be disposed at an angle of 90 to 135 degrees with respect to the motor shaft.

Preferably, there may be a motor shaft gear connected to the motor shaft, a propeller gear connected to the propeller shaft, wherein the motor shaft gear may be in meshing contact with the propeller gear.

Preferably, there may be a connecting member having a first end connected to the motor shaft and a second end connected to the propeller shaft. The connection transfers torque from the first motor to the first propeller.

Preferably, the linkage is a gear system.

Preferably, the drone is a fixed wing drone having a wing, wherein the motor is disposed within the wing and the propeller is disposed on a top side of the wing.

Preferably, the motor is an inner rotor motor.

Preferably, the drone is a multi-rotor drone having a body and at least one support arm connecting the body to at least one propeller, and wherein the motors are each disposed within the support arm.

A power train of a drone, wherein the drone has at least one lifting propeller driven by the power train, the power train including a motor having a motor shaft, and wherein the motor is disposed within a wing or support arm of the drone. There may be a connector to physically connect the motor shaft to the propeller to transfer torque from the motor shaft to the propeller.

Preferably, the motor shaft may be substantially perpendicular to the longitudinal axis of the wing or support arm on which the motor is located.

Preferably, the drone may be a vertical take-off and landing (VTOL) drone and the motor may be an inner rotor motor.

Preferably, the drone may be a fixed wing drone and the motor may be an inner rotor motor.

A method of reducing air drag in a drone may include placing a motor within a wing or support arm of the drone, wherein a motor shaft of the motor may be substantially parallel to a longitudinal axis of the wing or support arm on which the motor is located.

Preferably, the axis of rotation of the propeller may be perpendicular to the horizontal axis of the drone and the axis of rotation may be at an angle of between 90 and 135 degrees relative to the motor shaft.

Preferably, the axis of rotation may be at an angle of 90 degrees to the motor shaft.

Preferably, the motor may be placed within a first portion of the wing, wherein a thickness of a second portion of the wing directly adjacent to the first portion may be substantially similar to the thickness of the first portion.

Accordingly, the present disclosure is directed to an unmanned aircraft having a novel arrangement of its drivetrain, and a method of manufacturing an unmanned aircraft having an enhanced aerodynamic profile. The present disclosure also relates to a method of minimizing air resistance on an aircraft, whether the aircraft is manned or unmanned, and regardless of the size of the aircraft.

Preferably, the motor driving the lifting propeller is strategically placed where the motor shaft of the motor is not coaxial with the propeller shaft.

Preferably, the motor driving the lift propeller is strategically placed with the motor shaft of the motor at an angle between 90 degrees and 135 degrees to the propeller shaft.

Preferably, the motor driving the lift propeller may be strategically placed with the motor shaft of the motor at an angle between 45 degrees and 135 degrees to the propeller shaft.

Preferably, the motor driving the lift propeller is strategically placed with the motor shaft of the motor at an angle between 55 degrees and 135 degrees to the propeller shaft.

Preferably, the motor driving the lifting propeller may be strategically placed such that the motor shaft of the motor may be at an angle substantially parallel to the ground during flight.

Preferably, the motor driving the lifting propeller is connectable through a transmission such that the motor does not directly drive the lifting propeller.

Preferably, the motor driving the lifting propeller is connectable through a gear train, such that the motor indirectly drives the lifting propeller.

Preferably, the motor driving the lift propeller may be sized to fit within the support arm or wing to which the propeller is coupled, without the need for a separate motor housing.

Preferably, the motor driving the lift propeller can be carefully placed within the support arm or wing to which the propeller is coupled without substantially altering the outer aerodynamic profile of the support arm or wing.

Furthermore, it is contemplated that the aerodynamic profile of the drone may be improved by eliminating the use of a motor housing that houses the motor. Alternatively, the motor may be an internal rotor motor sized to fit within the support arm or wing.

Preferably, the transmission mechanism may be used to transmit the torque generated by the motor to the propeller, wherein the motor is not placed directly below the propeller shaft.

In many possible implementations of embodiments, the drone may have support arms that: there is more than one propeller on the same support arm. This one support arm may have more than one motor arranged within the same support arm in any of the methods disclosed. For example, a motor at one end of the support arm may indirectly drive the first propeller. Another motor at the opposite end of the support arm may indirectly drive another propeller. Alternatively, a third motor may be provided in the middle portion of the support arm (or anywhere between the two ends of the support arm) to indirectly drive the third propeller.

Another aspect of this embodiment is directed to a method of driving more than one propeller coupled to a single support arm, wherein each motor driving each propeller is discreetly placed within the single support arm such that the motor shaft of each motor is substantially parallel to the longitudinal axis of the single support arm. In this embodiment, the single support arm may have substantially the same outer profile throughout the length of the support arm.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any embodiments or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple partial implementations separately or in any suitable subcombination. Moreover, although features may be described above and below as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, operations, methods, or processes described herein may include more steps or fewer steps than those described. Further, the steps of these example operations, methods, or processes may be performed in an order different than that shown or described in the figures. Accordingly, other implementations are within the scope of the following claims.

The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

Drawings

It should be noted that the drawings may be in simplified form and may not be to precise scale. For convenience and clarity only, directional terms, such as top, bottom, left, right, upper, lower, above, below, rear, front, distal and proximal, are used with reference to the drawings in reference to the disclosure herein. Such directional terms should not be construed to limit the scope of the embodiments in any way.

FIG. 1 is a perspective view of a prior art fixed wing drone showing each wing with support arms and a bulky motor housing located at the end of each support arm.

Fig. 2 is a perspective view of a prior art VTOL multi-rotor drone showing four support arms and a bulky motor housing at the end of each support arm.

Fig. 3 is a bottom perspective view of one embodiment of a fixed-wing drone, showing each wing having a support arm and the distal end of each support arm having a low profile.

Figure 4 is a side perspective view of one embodiment of the support arm with a motor at its end, using gears to drive the propeller shaft, which in turn drives the propeller.

Figure 5 is a side perspective view of an exemplary support arm having three propellers, each propeller driven by a carefully positioned motor.

Fig. 6 is a side perspective view of another exemplary support arm having three propellers, each propeller driven by a carefully placed motor. The intermediate propeller is arranged at the bottom side of the support arm.

Fig. 7 is a side perspective view of yet another exemplary support arm having three propellers, each propeller driven by a carefully placed motor. One of the three propellers is located on the opposite side of the other two propellers.

Fig. 8 is a top perspective view of an embodiment of a VTOL multi-rotor drone in which the motor driving each propeller is discreetly disposed in each support arm.

Fig. 9 is a side perspective view of the embodiment of fig. 8.

Fig. 10 is an illustration of a considered VTOL multi-rotor drone, in which the motor driving each propeller is discreetly arranged within each support arm, and each support arm is at an oblique angle when the propellers are parallel to the ground.

Fig. 11 is an illustration of another contemplated VTOL multi-rotor drone, in which the motor driving each propeller is discreetly arranged within each support arm, and each support arm is at an oblique angle when the propeller is not parallel to the ground.

Figure 12 is a perspective side view of the distal end of the support arm of figure 10 showing the gears engaged at an oblique angle when the propeller is parallel to the ground.

Fig. 13 is a perspective side view of the distal end of the support arm of fig. 11 showing the gears meshing at right angles when the plane of rotation of the propeller is parallel to the longitudinal axis of the support arm.

FIG. 14 is a top perspective view of one embodiment of a fixed wing drone, with propellers disposed on the wings and motors driving the propellers discreetly disposed within the wings without substantially altering the external profile of the wings.

FIG. 15 is a front view of one embodiment of a fixed wing drone with propellers disposed on the tips of each of two wings. The motor driving each propeller is shown in this perspective view as being disposed in the wing without substantially altering the aerodynamic profile of the wing, as the motor is carefully positioned.

FIG. 16 is a front view of an embodiment of a fixed wing drone with two propellers disposed on each of two wings. The electric motor driving each propeller is shown in this perspective view as being provided in the wing without substantially altering the aerodynamic profile of the wing, since the motor is carefully positioned.

FIG. 17 is a front view of one embodiment of a fixed wing drone with propellers disposed on a mid-portion of each of two wings. The motor driving each propeller is shown in this perspective view as being disposed in the wing without substantially altering the aerodynamic profile of the wing, as the motor is carefully positioned.

FIG. 18 is a cross-sectional view of the airfoil of FIG. 16 illustrating engagement of two gears to transfer torque from a motor to a propeller in accordance with an aspect of the disclosed embodiments.

Detailed Description

Various aspects of the various embodiments may now be better understood by turning to the following detailed description of the embodiments, given as exemplary embodiments of the embodiments defined in the claims. It is expressly understood that the embodiments defined by the claims may be broader than the illustrated embodiments described below.

As used herein, the term "drone" refers to an unmanned aerial vehicle, whether it is unmanned (i.e., UAV) or designed to carry passengers. For example, it may be a fixed-wing aircraft that is portable enough to be carried in one child's hand, may be a fixed-wing aircraft that is large enough to carry more than a few passengers, or may be any such aircraft that falls between these two extremes in weight and size. In one example, it may be a multi-rotor aircraft small enough to fit in the palm of a user's hand, may be a multi-rotor aircraft large enough to carry more than a few passengers, or may be a multi-rotor aircraft sized to fall between these two extreme examples.

The inventors have found that the aerodynamic profile of an unmanned aircraft is generally negatively affected by the size and shape of the motor driving the lift propeller. The lift propellers of a drone are commonly found in multi-rotor drones. Some fixed wing drones may also have lift propellers to enable the fixed wing drone to take off and land vertically.

Referring first to fig. 1, fig. 1 generally depicts a basic model of a fixed-wing drone 100. In this prior art fixed-wing drone 100, the fixed-wing drone 100 has a fuselage 2 and two main wings 30, the main wings 30 extending from the front of the fuselage 2. A support arm 20 is provided on each main wing 30. The support arm 20 has a generally elongated tubular configuration with one end extending beyond the leading edge of the main wing 30 and the opposite end extending to the trailing edge of the main wing 30. The primary purpose of the support arm 20 in the prior art drone 100 is to retain and support the motor housing at the distal end of the support arm 20. The support arm 20 is generally elongate in shape so as to hold the motor housing 41 away from the main wing 30. The motor housing 41 in these prior art designs typically has a very large, short, cylindrical outer profile with a central axis that is substantially perpendicular to the central axis of the support arm 20. To some extent, the prior art motor housing 41 and support arm 20 are similar in construction to a hammer head and hammer handle. Some drone manufacturers have attempted to disguise the awkward structure by masking the structure with an aerodynamic shell (not shown) to make the entire drone bulky, albeit with more aerodynamic performance. Below the bulky aerodynamic shell of such prior art designs, a bulky motor directly driving the propeller is reserved, the propeller being located directly above the bulky motor.

The prior art fixed wing drone has a vertical stabilizer 4 at its aft end, and two horizontal stabilizers 6 attached to the vertical stabilizer 4. On each horizontal stabilizer, there is an elevator that adjusts the pitch angle of the drone 100. On the trailing edge of the vertical stabilizer 4, there is a rudder to control the yaw angle of the drone 100.

In fig. 2, a prior art VTOL multi-rotor drone 200 is known having a body 1 with support arms 20 extending radially from the body 1. In this particular example, there are four support arms 29 extending radially from the body 1. On the distal end of each support arm 20 is a motor housing 41, the motor housing 41 enclosing a motor which directly drives the lifting propeller 10 directly above it. The camera 3 is disposed under the body 1 to take an aerial photograph of a predetermined target under. As discussed above, the support arm 20/motor housing 41 combination resembles a hammer and creates an obstruction due to its aerodynamic profile. Attempts have been made to improve the aerodynamic profile by covering the combination of the support arm 20 and the motor housing 41 with a more bulky but more aerodynamic housing (not shown). However, the arrangement and design of the internal components in these prior art VTOL multi-rotor drones remains intact.

Referring now to the details of fig. 3, a fixed wing drone is shown having a fuselage 102 and two main wings 130, the main wings 130 extending from both sides of the fuselage 102. On each of the two main wings 130, a support arm 120 may be provided, the support arm 120 extending across a middle portion of the main wing 130 with a front end extending beyond a leading edge of the main wing 130 and a rear end extending beyond a trailing edge of the main wing 130. Two propellers 110 are coupled to each support arm 120. In this particular embodiment, the propeller 110 is located on the end of the support arm 120. Unlike prior art designs, no motor housing is provided beneath each propeller 110.

In other words, as shown in fig. 3, each of the support arms 120 is free from attachment at its ends to objects that are substantially larger or wider than the support arms 120 themselves. Indeed, the support arm 120 in this particular embodiment may minimize air resistance and improve the aerodynamic profile of the drone.

As shown in fig. 3, the fixed wing drone also has a vertical stabilizer 104 at the aft end of the drone. A rudder 109 is attached to the vertical stabilizer 104 to change the yaw angle of the drone. Near the top of the vertical stabilizer 104 are two horizontal stabilizers 106. Attached to the trailing edge of each of the two horizontal stabilizers 106 is an elevator that changes the pitch angle of the drone.

As one of ordinary skill in the art will appreciate, the version of the drone as shown in FIG. 3 is but one example of the disclosed embodiments. The position of the lift fan 110 may be readily varied according to the aesthetic or functional needs of a particular application. For example, the drone may be a canard or a multi-rotor drone, as will be described below.

In other examples, which will be discussed later, the lifting screw 110 may even be arranged in a part of the supporting arm 120, or the lifting screw 110 may even be arranged anywhere on the main wing 130.

Although this particular embodiment discloses the use of 2-bladed propellers 110, it should be understood that other numbers of blades may be used for each propeller 110.

Contemplated fixed wing drones may be made of suitable lightweight materials to withstand extreme weather conditions, including natural and synthetic polymers, various metals and metal alloys, naturally occurring materials, textile fibers and all reasonable combinations thereof.

Fig. 4 shows one way how the inner parts are arranged to drive the lifting propeller as described in fig. 3. In fig. 4, as shown in fig. 4, the end of the support arm 120 may be wrapped around a motor 140 to drive the propeller 110. The motor 140 may have a motor shaft 141, and the motor shaft 141 is generally disposed near a central axis region of the motor 140. The motor shaft 141 rotates, thereby turning the driving gear 142, which may be directly attached to the motor shaft 141. The drive gear 142 may be in meshing contact with the propeller gear 144. The plane of rotation of the drive gear 141 is at right angles to the plane of rotation of the propeller gear 144. As will be described later in other embodiments, the plane of rotation of drive gear 141 and the plane of rotation of propeller gear 144 may be at angles other than right angles, depending on the particular design and application of the drone.

As further shown in fig. 4, the motor shaft 141 may be substantially parallel to the longitudinal axis of the support arm 120. In some embodiments, such as the embodiment shown in fig. 4, the motor shaft 141 may be substantially coaxial with the longitudinal axis of the support arm 120.

The operation of this embodiment is straightforward. The motor 140 may be powered by a power source (not shown) and its motor shaft 141 rotates, thereby rotating the drive gear 142. The driving gear 142 also rotates the propeller gear 144 while being engaged with the propeller gear 144. The propeller gear 144 may be attached to the propeller shaft 114, and the propeller shaft 114 may be attached to the blades of the propeller 110. Each propeller blade has a tip 112 and a root 113. The root 113 of the propeller 110 may be connected to a propeller shaft 114 via a hub 111.

In the embodiment shown in fig. 4, a portion of the propeller shaft 114, the entire propeller gear 144, the entire drive gear 142, and the entire motor 140 are enclosed within or near the support arm tip 122.

The embodiment of fig. 3 may also be used in a canard unmanned aerial vehicle with canard wings at the front. Wherein each support arm 120 may span the main wing 130 and the canard wing. By spanning the main wing 130 and the canard wing, structural integrity is enhanced. Each support arm 120 may have more than two lifting propellers 110. Here, in addition to having two lifting screws 110 located at opposite ends of the support arm, respectively, a third lifting screw 110 is arranged near the middle part of the support arm 120.

The front lifting propeller 110 may face downward, the middle lifting propeller 110 may face upward, and the rear lifting propeller 110 may face downward. This arrangement may allow two adjacent lifting propellers 110 to be arranged closer together such that their circular ranges of motion may overlap in top view, but their blades do not physically contact each other. Whether the lift fan 110 is facing up or down, they may be designed to push the air downward depending on the angle of the fan blades and/or the direction in which the fan is rotating.

Other possible arrangements are also possible. Fig. 5 shows an embodiment in which all three lifting propellers 110 of the support arm 120 may be directed upwards. Fig. 6 shows an embodiment in which the two end lifting propellers 110 of the support arm 120 may face upwards, while the middle lifting propeller 110 may face downwards. Fig. 7 shows another embodiment, in which one end lifting propeller 110 of the support arm 120 may face upwards, while the other two lifting propellers 110 may face downwards.

It is important to understand that in the embodiment of fig. 3, a good aerodynamic profile is particularly desirable since fixed wing drone 200 is generally capable of flying at relatively faster speeds than multi-rotor drone 100. For any fast flying drone, aerodynamic profile and air resistance are important issues that may affect the power/fuel consumption, speed and endurance of the aircraft. By having a very small motor to directly drive the propeller, simply miniaturizing the prior art design would not be feasible for a small drone because the support arm 120 in such a drone is too small to wrap a motor large enough to directly drive the propeller 110. Direct drive is defined as using a motor to drive the propeller, wherein the motor shaft and the propeller shaft of the motor are coaxial.

In the contemplated embodiment, the motor 140 may be any type of motor capable of generating a sufficient amount of torque. Particularly contemplated are internal rotor motors.

Fig. 8 generally depicts the basic design of a contemplated embodiment in which a VTOL multi-rotor drone may implement the powertrain design of the present disclosure. In fig. 8, the VTOL multi-rotor drone may have four support arms 120, each support arm 120 supporting a lifting propeller 110. Although only four support arms 120 and four lifting propellers 110 are shown, one of ordinary skill in the art will immediately recognize that other numbers of support arms 120 and lifting propellers 110 may also implement the powertrain design of the present disclosure. For example, a VTOL multi-rotor drone having six support arms, each with two lift propellers (one at the top and one at the bottom, both coaxial at the distal end of the support arms) may also implement the powertrain system of the present disclosure.

The VTOL multi-rotor drone in fig. 8 may have an optional camera 103 attached under the body 101. Each lift rotor 110 has a root 113 and is attached to the rotor shaft via a hub 111 as previously described. These lifting propellers 110 may be arranged at or near the support arm tip 122 of each support arm 120.

As further shown in fig. 9, each support arm 120 is substantially horizontally flush with the body 101 of the drone.

There may be designs where each support arm 120 is angled with respect to the body 101 of the drone. In fig. 10 and 11, the support arm 120 is at a fixed angle that is tilted upward. The design in fig. 10 differs from the design in fig. 11 in that the plane of rotation of their lifting propeller is different. In fig. 10, the plane of rotation of its lifting propeller is at an angle of about 45 degrees to the longitudinal axis of the support arm 120 to which the lifting propeller 110 is coupled. In fig. 11, the plane of rotation of its lifting propeller is maintained substantially parallel to the longitudinal axis of the support arm 120 to which the lifting propeller 110 is coupled.

Fig. 12 and 13 show the meshing of the drive gear 142 with the propeller gear 144 in the design of fig. 11 and 12.

As shown in fig. 12, an exemplary drivetrain is illustrated, wherein the plane of rotation of the lifting propeller may be at an angle of about 45 degrees to the longitudinal axis of the support arm 120 to which the lifting propeller 110 is coupled. In other words, the drive gear 142 may be engaged to the propeller gear 144 at about 45 degrees. The motor shaft 141 of the motor 140 is substantially parallel to the longitudinal axis of the support arm 120.

With respect to fig. 12, an exemplary drivetrain is shown wherein the plane of rotation of the lifting propeller may be at an angle of approximately 90 degrees to the longitudinal axis of the support arm 120 to which the lifting propeller 110 is coupled. In other words, the drive gear 142 may be engaged to the propeller gear 144 at about 90 degrees. The motor shaft 141 of the motor 140 is substantially parallel to the longitudinal axis of the support arm 120. However, support arm 120 is angled relative to the horizontal axis of the VTOL multi-rotor drone.

In other embodiments, the drive gear 142 may mesh with the propeller gear 144 between 40-90 degrees.

FIG. 13 illustrates just one example of the powertrain of FIG. 11 in greater detail. Here, the arrangement is similar to that described previously and shown in fig. 4, except that the arrangement in fig. 13 has the support arm 120 at a fixed inclination angle.

Although the above embodiments disclose the use of drive and propeller gears meshed together to transmit torque at an angle without shaft or direct drive, it should be understood that other types of connectors or transmission gears or linkages may be used to perform the same function as the disclosed gears.

Contemplated gears may be made of suitable materials to withstand temperature extremes and durability over time, including natural and synthetic polymers, various metals and metal alloys, naturally occurring materials, textile fibers, glass and ceramic materials and all reasonable combinations thereof.

FIG. 14 generally depicts the basic structure of a fixed wing drone according to one of the disclosed embodiments. Here, the main wing 130 is coupled to the body 102, and may have a propeller 110 attached to a tip 131 of the main wing 130. The propeller 110 has a blade tip 112 and a blade root 113. The propeller 110 is coupled to the main wing 130 via a hub 111. The propeller 110 may be driven with a similar arrangement of carefully placed motors and gears.

The propeller 110 allows the fixed wing drone to take off and land vertically and allows for its placement in various positions on the main wing 130.

In one particular embodiment as shown in fig. 15, the fixed wing drone may have two fixed wings 130, and each of the two fixed wings 130 may have a propeller 110 attached to its distal end.

In another particular embodiment as shown in fig. 16, the fixed wing drone may have two fixed wings 130, and each of the two fixed wings 130 may have two propellers 110 attached thereto. One located at the distal end of the wing 130 and the other located in the middle portion of the wing 130.

In yet another particular embodiment as shown in fig. 17, the fixed wing drone may have two fixed wings 130, and each of the two fixed wings 130 may have one propeller 110 attached to it in a portion of the wings 130.

These particular designs allow the fixed-wing drone to have a propeller 110 without the need for support arms. The support arm may add additional weight to the drone and may negatively impact the aerodynamic profile of the drone.

As further shown in fig. 18, a side perspective view of the wing 130 is shown with the motor disposed within the wing 130 with the motor shaft substantially parallel to the longitudinal axis of the wing 130. The motor shaft is attached to a drive gear 142, the plane of rotation of the drive gear 142 being perpendicular to the plane of rotation of the propeller 110. The drive gear 142 meshes with the propeller gear 144. When the drive gear 142 rotates, the propeller gear 144 also rotates. The ratio of the two gears may vary.

The propeller gear 144 is attached to the propeller shaft 114. When the propeller gear 144 rotates, it also rotates the propeller shaft 114 in the same direction. Propeller shaft 114 is connected to the propeller blades via hub 111. The propeller blades consist of a root portion 113 and a tip portion 112.

It should be particularly noted that although only helical gears are shown in the figures, all types of gears are contemplated for use with any of the embodiments disclosed herein. For example, the following types of gears or combinations thereof may be used: straight gears, helical gears, parallel helical gears, internal gears, external gears, helical bevel gears, helical gears, crossed helical gears, straight bevel gears, worm gears, and hypoid gears.

It should also be particularly noted that although two meshing gears of similar size and diameter are shown in the figures, either of the disclosed embodiments may use gears of different sizes and gear ratios to achieve different torque outputs or speed outputs.

One aspect of the present invention is directed to a method of improving the aerodynamic profile of a drone, whether a multi-rotor drone or a fixed-wing drone. In one aspect of the disclosure, the method includes placing the drive motor within a wing or support arm coupled to the propeller. The drive motor may be disposed within the wing or support arm, with the motor shaft being substantially parallel to the longitudinal axis of the support arm or wing in which the motor is disposed.

Contemplated methods may further include indirectly driving the lift propeller using the connector such that the motor may still drive the lift propeller even if a longitudinal axis of a motor shaft of the motor is not coaxial with the propeller shaft.

Alternatively, contemplated methods may include indirectly driving the lifting propeller using a connector such that the motor may still drive the lifting propeller even if the longitudinal axis of the motor shaft of the motor is at an angle to the propeller shaft. This angle may be between 75 degrees and 135 degrees. In another embodiment, the angle may be any value between 90 degrees and 120 degrees. In yet another embodiment, the angle may be any value between 90 degrees and 85 degrees.

Similarly, while operations and/or methods may be depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations and/or method steps be performed, to achieve desirable results. In some cases, multi-threading and parallel processing may be advantageous.

Many changes and modifications may be made by one having ordinary skill in the art without departing from the spirit and scope of the disclosed embodiments. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example, and that it should not be taken as limiting the embodiments defined by the following claims. For example, notwithstanding the fact that the elements of a claim are set forth below in a certain combination, it must be expressly understood that the embodiments include other combinations of fewer, more or different elements, which are disclosed herein, even if not initially claimed in such combinations.

Thus, specific embodiments and applications of a lightweight motor for a drone have been disclosed. It will be apparent, however, to one skilled in the art that many more modifications besides those already described are possible without departing from the concepts herein disclosed. Accordingly, the disclosed embodiments are not limited, except as by the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms "comprises" and "comprising" should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Insubstantial changes from the claimed subject matter as viewed by a person with ordinary skill in the art, now known or later devised, are expressly contemplated as being equivalently within the scope of the claims. Accordingly, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements. The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what incorporates the essential idea of the embodiment. Additionally, where the specification and claims refer to at least one selected from the group consisting of a, B, c. Text should be interpreted as requiring at least one element from a combination comprising N, instead of a + N, or B + N, etc.

The words used in this specification to describe various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself.

The definitions of the words or elements of the following claims, therefore, include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. In this sense it is therefore contemplated that an equivalent substitution of two or more elements may be made for any one of the elements in the claims below or that a single element may be substituted for two or more elements in a claim. Although elements may be described above as acting in certain combinations and even initially claimed as such, it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

1. A drone, characterized in that it comprises:

the support arm is provided with a first propeller, a second propeller and a third propeller, the first propeller and the third propeller are respectively arranged on the top sides of the two tail ends of the support arm, and the second propeller is arranged on the bottom side of the middle end of the support arm;

the first propeller to the third propeller are provided with respective propeller shafts which are perpendicular to the horizontal axis of the unmanned aerial vehicle, the first propeller to the third propeller are driven by a first motor to a third motor in a one-to-one correspondence mode, and the first motor to the third motor are provided with respective motor shafts;

and wherein the propeller shafts are arranged at a 90 degree angle relative to the corresponding motor shafts, the first to third motors being disposed within a support arm of the drone without altering the outer aerodynamic profile of the support arm.

2. The drone of claim 1, further comprising: a motor shaft gear coupled with the motor shaft, a propeller gear coupled with the propeller shaft; the motor shaft gear is in meshing contact with the propeller gear.

3. The drone of claim 1, further comprising a connector having a first end and a second end, the first end connecting the motor shaft and the second end connecting the propeller shaft, the connector transmitting torque from the first motor to the first propeller.

4. The drone of claim 1, wherein the first to third motors are inner rotor motors.

5. A power train of a unmanned aerial vehicle, the unmanned aerial vehicle is provided with a lifting propeller driven by the power train, the unmanned aerial vehicle comprises a main body and at least one supporting arm connected with the main body, a first propeller, a second propeller and a third propeller are arranged on the supporting arm, the first propeller and the third propeller are respectively arranged on the top sides of two tail ends of the supporting arm, and the second propeller is arranged on the bottom side of the middle end of the supporting arm;

the power train includes:

a motor having a motor shaft,

wherein the motor is disposed within a support arm of the drone and does not alter an outer aerodynamic profile of the support arm,

wherein the motor shaft is substantially parallel to a longitudinal axis of the support arm on which the motor is located;

and

a connector physically connecting the motor shaft to the lifting propeller to transfer torque from the motor shaft to the lifting propeller.

6. The powertrain of claim 5, wherein the connector is a gear set.

7. The powertrain of claim 6, wherein the drone is a VTOL drone and the motor is an internal rotor motor.

8. The powertrain of claim 6, wherein the drone is a fixed wing drone and the motor is an internal rotor motor.

9. The method for reducing the air resistance in the unmanned aerial vehicle is characterized by being applied to the unmanned aerial vehicle, wherein the unmanned aerial vehicle comprises a main body and at least one supporting arm connected with the main body, a first propeller, a second propeller and a third propeller are arranged on the supporting arm, the first propeller and the third propeller are respectively arranged on the top sides of two tail ends of the supporting arm, and the second propeller is arranged on the bottom side of the middle end of the supporting arm; the method comprises the following steps:

placing a motor within a support arm of the drone without altering an outer aerodynamic profile of the support arm, wherein a motor shaft of the motor is substantially parallel to a longitudinal axis of the support arm on which the motor is located; and driving a propeller via a gear with the motor to provide a lifting force.

10. The method of claim 9, wherein the axis of rotation of the propeller is perpendicular to a horizontal axis of the drone, and the axis of rotation is at a 90 degree angle relative to the motor shaft.

11. The method of claim 9, wherein the motor is an internal rotor motor.

12. The method of claim 10, wherein the motor is positioned within a first portion of a support arm, wherein a second portion of the support arm immediately adjacent the first portion has a thickness equal to the first portion.