Unmanned aerial vehicle propulsion system

Abstract

The invention relates to a propulsion system comprising a motor disposed at a central portion of the propulsion system, the motor further comprising a rotor shaft. The system includes a diverter gearbox coupled to the rotor shaft, the diverter gearbox further including at least one diverter output shaft. The system includes at least one continuously variable transmission (CVT) coupled to the diverter output shaft, the CVT further including a driveshaft. The system comprises at least one bevel gear box, the bevel gear box comprises a bevel gear box input shaft and a bevel gear box output shaft, the bevel gear box input shaft is arranged parallel to the horizontal plane, and the bevel gear box output shaft is arranged at an angle to the bevel gear box input shaft. Wherein the bevel gear box input shaft is coupled to the transmission shaft. The system includes at least one propeller coupled to the bevel gear box output shaft.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Patent Application No. 18 / 113,436, filed February 23, 2023. The entire teachings of the above application are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0003] The disclosed subject matter relates to a system for a propulsion system. In particular, the disclosed subject matter relates to a propulsion system utilizing a continuously variable transmission (CVT) configured for use with a drone. BACKGROUND

[0004] Generally, multicopter aircraft of various sizes, but primarily micro aircraft or hobbyist aircraft, are unmanned aerial vehicles (UAVs) that use three or more rotors as well as fixed pitch rotors to generate lift. By varying the speed of the rotors such that the generated thrust is greater than, equal to, or less than the gravitational and drag forces acting on the aircraft, the drone (aircraft) can be made to ascend, hover, or descend. Standard drones employing a quadcopter configuration utilize four motors (one propeller per motor) mounted on arms or towers to generate thrust and provide lift to the aircraft. In this configuration, two of the motors spin counterclockwise and the other two spin clockwise. According to the conservation of angular momentum, this configuration cancels out the torque generated by each motor with the opposite direction of rotation of the corresponding propeller. Varying the speed of the reaction rotors will cause the quadcopter to rotate clockwise (CW) or counterclockwise (CCW) about its axis.

[0005] The maximum takeoff weight of an aircraft is limited by the thrust capability, energy and power storage, and the propulsion method / configuration. The goal of any aircraft is to be as light as possible and as powerful as possible. A CVT is the ideal type of transmission because it has an infinite ratio between its minimum and maximum ranges, which is exactly what is needed for smooth and precise control of propeller speed. Thus, there remains a need for an efficient and economical method and system for a drone propulsion system as described herein. SUMMARY

[0006] The purposes and advantages of the disclosed subject matter will be set forth in and apparent from the following description, and will be achieved by the methods and systems as hereinafter described in the written description and claims hereof, as well as in the appended drawings. Additional advantages of the disclosed subject matter will be realized and attained by the methods and systems particularly pointed out in the written description and claims hereof, as well as in the appended drawings.

[0007] To achieve these and other advantages and in accordance with the purpose of the disclosed subject matter, as embodied and broadly described, the disclosed subject matter includes a propulsion system. The propulsion system includes an electric machine disposed at a central portion of the propulsion system, the electric machine further including a rotor shaft. The propulsion system includes a splitter gearbox coupled to the rotor shaft, the splitter gearbox further including at least one splitter output shaft. The propulsion system includes at least one continuously variable transmission (CVT) coupled to the splitter output shaft, the CVT further including a drive shaft. The propulsion system includes at least one bevel gearbox including a bevel gearbox input shaft and a bevel gearbox output shaft, the bevel gearbox input shaft disposed parallel to a horizontal plane and the bevel gearbox output shaft disposed at an angle to the bevel gearbox input shaft, and the bevel gearbox input shaft coupled to the drive shaft. The propulsion system includes at least one propeller coupled to the bevel gearbox output shaft.

[0008] The disclosed subject matter also includes a propulsion system. The present invention relates to a propulsion system including an electric machine disposed at a central portion of the propulsion system, the electric machine further including a rotor shaft. The propulsion system includes a splitter gearbox coupled to the rotor shaft, the splitter gearbox further including four splitter gearbox output shafts extending radially from the splitter gearbox at 90 degree intervals, and wherein each of the splitter gearbox output shafts is disposed in a horizontal plane. The propulsion system includes four continuously variable transmissions (CVTs), each CVT coupled to one of the splitter gearbox output shafts, and wherein each of the CVTs is disposed proximate the splitter gearbox, each CVT further including a drive shaft, wherein each of the four drive shafts extends radially and respectively co-linearly with each of the splitter gearbox output shafts. The propulsion system includes four bevel gearboxes, each bevel gearbox coupled to one of the drive shafts, the bevel gearbox including a bevel gearbox input shaft and a bevel gearbox output shaft, the bevel gearbox input shaft disposed co-planar to the splitter gearbox output shaft, and the bevel gearbox output shaft disposed at a right angle to the gearbox input shaft. The propulsion system includes at least four propellers, each of the propellers coupled to one of the bevel gearbox output shafts, each propeller configured to rotate parallel to the horizontal plane about each of the bevel gearbox output shafts.

[0009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further explanation of the disclosed subject matter claimed.

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to illustrate and provide a further understanding of the methods and systems of the subject matter disclosed. These drawings are illustrative of the principles of the subject matter and should not necessarily be considered to be restrictive of the principles. BRIEF DESCRIPTION OF DRAWINGS

[0011] Reference is made to the drawings, which illustrate various aspects and features of the subject matter described herein and, by way of example only, the examples of which can be implemented in accordance with the principles of the subject matter. The drawings are illustrative and are not necessarily drawn to scale, with some components and features being exaggerated for clarity. The drawings demonstrate various aspects and features of the subject matter and can illustrate one or more embodiments or examples of the subject matter in whole or in part.

[0012] Figure 1 is a schematic illustration of a UAV propulsion system in accordance with the disclosed subject matter.

[0013] Figure 2 is a cross-sectional view of an exemplary embodiment of a propulsion system in accordance with the disclosed subject matter.

[0014] Figure 3 is a cross-sectional view of an embodiment of a CVT in accordance with the disclosed subject matter.

[0015] Figure 4A -B is a schematic illustration of a UAV propulsion system in accordance with the disclosed subject matter.

[0016] Figure 5 is a plan view of a multi-copter UAV in accordance with aspects of the disclosed subject matter.

[0017] Figure 6A -C is a front and back isometric view of an embodiment of a CVT in accordance with the disclosed subject matter.

[0018] Figure 7 is a block diagram of a compute node in accordance with the disclosed subject matter. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to exemplary embodiments of the subject matter disclosed, examples of which are illustrated in the accompanying drawings. The methods and corresponding steps of the disclosed subject matter will be described with reference to the systems.

[0020] The methods and systems presented herein can be used in propulsion systems. The disclosed subject matter is particularly suited for propulsion systems utilizing a continuously variable transmission configured for use in a UAV. For purposes of explanation and illustration, and not limitation, Figure 1An exemplary embodiment of a system in accordance with the disclosed subject matter is shown and generally designated by reference number 100. In the various views and drawings presented herein, similar reference numbers (distinguished by a leading digit) can be provided to represent functionally corresponding but not necessarily identical structures.

[0021] Reference is now made to Figure 1 A schematic diagram of the propulsion system 100 is presented in block diagram form. It should be noted that this schematic diagram utilizes dashed and solid lines arrangements. For the purposes of this disclosure, some components can be mechanically connected, electrically connected, communicatively connected, or a combination thereof. Both mechanical communication and electrical or electromagnetic communication can be referred to in this disclosure, and any of the components described herein can be connected to any other component in a suitable arrangement.

[0022] With continued reference to Figure 1 The system 100 includes an electric machine 104. The electric machine 104 includes at least a rotor shaft. The electric machine 104 can be configured to generate one or more magnetic fields in order to rotate a rotor shaft disposed therein. For example, and without limitation, the electric machine 104 can include one or more windings wound on a stator, which are configured as an electromagnet or electromagnets. The electric machine 104 can alternate one or more magnetic fields to attract and / or repel one or more permanent magnets attached to a portion of the rotor shaft. In various embodiments, the electric machine 104 can include one or more permanent magnets disposed within or forming a stator disposed about the rotor shaft. The permanent magnet stator can attract and repel electromagnet portions (e.g., conductive material windings) about the rotor shaft. It will be appreciated by one of ordinary skill in the art, in light of the disclosed subject matter, that a variety of electric motor arrangements can be utilized. The electric machine 104 can be configured to rotate the rotor shaft about an axis of the rotor shaft (i.e., a reversible torque) in two directions (clockwise and counterclockwise).

[0023] With continued reference to Figure 1 The electric machine 104 can be an electric motor. The electric machine 104 can be a direct current (DC) and / or an alternating current (AC) electric motor. In various embodiments, the electric machine 104 can be an induction motor, a synchronous motor, a commutator motor, a wound rotor motor, and / or a squirrel cage motor. In various embodiments, the electric machine 104 can be a shunt-wound motor, a series-wound motor, a permanent magnet DC (PMDC) motor, a compound-wound motor, and / or a separately-excited motor. In various embodiments, the electric machine 104 can be a stepper motor, a brushless motor, a servo motor, a universal motor, and / or a reluctance motor. In various embodiments, the electric machine 104 can be a brushless electric motor. The electric machine 104 can be any configuration of a component configured to convert electrical energy into rotational or translational motion. In various embodiments, the electric machine 104 can be a brushed motor, a single-, two-, three-, or multi-phase motor, an axial or radial flux motor. In various embodiments, the electric machine 104 can be air-cooled and / or liquid-cooled.

[0024] With continued reference to Figure 1 , the electric machine 104 can be an internal combustion engine. In various embodiments, the electric machine 104 can be a piston-driven combustion engine. In various embodiments, the electric machine 104 can be a Wankel or a rotary engine. In various embodiments, the electric machine 104 can utilize the combustion of one or liquid, vaporized, or gaseous fuels to move one or more components, such as a crankshaft. In various embodiments, the electric machine 104 can be a carbureted, fuel-injected, or variable valve fuel-injected. In various embodiments, the electric machine 104 can be a one-, two-, four-, six-, eight-, ten-, twelve-, or more piston engine. In various embodiments, the electric machine 104 can be a horizontally opposed engine, a one- stroke, two-stroke, four-stroke, or other configuration engine. In various embodiments, the electric machine 104 can be a ring-arranged piston-driven engine, where pistons are disposed radially around a crankshaft, and the combustion of fuel in multiple pistons rotates a centrally disposed shaft.

[0025] In various embodiments, multiple electric machines can be utilized, with the rotor shaft of each of these electric machines transmitted to a central output shaft for actuation of downstream components. In various embodiments, the electric machine 104 can be disposed at a central portion of the propulsion system 100. The electric machine 104 can be disposed at a relative center of a radially symmetric system, as referenced Figure 3 As can be readily seen, the electric machine 104 can be disposed such that the rotor shaft is disposed substantially vertically (perpendicular to the ground when the system is installed on a drone). In various embodiments, the electric machine 104 itself can be radially symmetric, with the housing containing the stator, windings, magnets, and rotor shaft comprising a substantially cylindrical form. In various embodiments, the rotor shaft can be oriented in a horizontal plane parallel to the ground, with the rotor shaft mechanically coupled to one or more other components, as will be discussed herein below. In various embodiments, the rotor shaft can be disposed substantially vertically, but oriented downward (facing the ground when installed on a drone). In various embodiments, the rotor shaft can be disposed about another angle relative to a vertical axis and a horizontal plane, such as 45 degrees relative to vertical, and about a vertical axis in some radial direction. One of ordinary skill in the art will appreciate that multiple arrangements of the electric machine 104 can be configurable for use with the systems disclosed herein.

[0026] With continued reference to Figure 1The system 100 includes a splitter gearbox 108. The splitter gearbox 108 can be disposed at the center of the system 100, such as above or below the motor 104 at the center of a radially symmetric system. The splitter gearbox 108 is configured with an input shaft that is mechanically coupled to the rotor shaft of the motor 104. In various embodiments, the input shaft of the splitter gearbox can be coupled to a collective output shaft that delivers multiple motor output rotations into a single output shaft. The splitter gearbox input shaft can include splines, teeth, ridges, gears, or similar features configured to mechanically couple the shafts to one another. In various embodiments, the input shaft of the splitter gearbox 108 is collinear with the output shaft of the motor 104. In various embodiments, the input shaft of the splitter gearbox 108 is not collinear with the rotor shaft of the motor 104. In various embodiments, the input shaft of the splitter gearbox 108 and the rotor shaft of the motor 104 are disposed at an angle to one another, mechanically coupled by a universal joint or similar shaft coupling. In various embodiments, the rotor shaft of the motor 104 and the input shaft of the splitter gearbox 108 are mechanically coupled to an intermediate assembly configured to deliver torque between the shafts, such as a gearbox configured to change the torque delivered between the shafts or the arrangement of the shafts relative to one another.

[0027] Further reference is made to Figure 1 The splitter gearbox 108 can be formed as a substantially cuboid body. The input shaft can be disposed through a first face of the cuboid, and the output shaft can be disposed through at least one of the immediately adjacent side faces, thereby disposed orthogonally to the input shaft. In various embodiments, the splitter gearbox input shaft and at least one splitter gearbox output shaft are disposed in different planes. In various embodiments, the splitter input shaft and the splitter output shaft are disposed orthogonally to one another, disposed in the same plane. In various embodiments, the splitter input shaft and the splitter output shaft are disposed at an acute angle relative to one another, in the same plane. In various embodiments, the splitter input shaft and the splitter output shaft are disposed at an obtuse angle relative to one another, disposed in the same plane. In various embodiments, the splitter input shaft and the splitter output shaft are disposed orthogonally to one another, disposed in different planes.

[0028] In various embodiments, the shunt input shaft and the shunt output shaft are disposed at an acute angle relative to each other while disposed in different planes. In various embodiments, the shunt input shaft and the shunt output shaft are disposed at an obtuse angle relative to each other while disposed in different planes. In various embodiments, there are multiple shunt output shafts, each disposed radially equidistant from each other, with the shunt input shaft intersecting the radial center of the shunt output shafts. In various embodiments, the shunt output shafts are disposed radially irregularly around the shunt gear box, with the shunt input shaft intersecting the radial center of the shunt output shafts. In various embodiments, the shunt gear box 108 is not radially symmetric, with multiple shunt output shafts disposed substantially in the same direction, which is different from the direction of extension of the shunt input shaft.

[0029] With continued reference to Figure 1 , each of the shunt output shafts can include splines, ridges, teeth, or other features configured to help the shafts mechanically couple to one or more other components. For example, but not limited to, each of the multiple shunt output shafts can be configured as a splined shaft, where the shaft includes grooves cut along the length of the shaft at predetermined distances along the shaft. For example, but not limited to, the shaft can be coupled to one or more shafts via a collar that includes features configured to couple to the teeth on the splined shaft. The collar can then be further coupled to another shaft via the same or similar interlocking teeth mechanism around the exterior of the shaft and the interior of the collar.

[0030] With continued reference to Figure 1 , the shunt gear box can include multiple shunt output shafts that can rotate in the same or different directions. For example, but not limited to, each shunt output shaft can rotate in an alternating pattern, as in an embodiment where there are four shunt output shafts, each shunt output shaft rotates in a direction opposite to the direction of rotation of the two shunt output shafts directly adjacent on both sides. In that embodiment, the four shunt output shafts are disposed orthogonally to each other in a horizontal plane at 90 degrees intervals.

[0031] With continued reference to Figure 1In various embodiments, system 100 includes at least one continuously variable transmission (CVT) 112. CVT 112 is coupled to the splitter output shaft. In embodiments where there are multiple splitter output shafts, each splitter output shaft can be coupled to a different CVT 112. For example, but not by way of limitation, the splitter output shafts can be relatively short such that each CVT 112 is coupled proximate to the splitter gear box 108. In various embodiments, CVT 112 can be attached to a face of the splitter gear box 108, where the coupling from the splitter output shaft to CVT 112 is not load bearing and is only used to transfer torque between shafts. In various embodiments, CVT 112 is configured to have an input shaft and a drive shaft. The input shaft of CVT 112 is mechanically coupled to the splitter output shaft.

[0032] With continued reference to Figure 1 CVT 112 is configured to transfer torque from the splitter gear box 108 to the bevel gear box 116, which will be discussed in greater detail below. CVT 112 is configured to continuously adjust the torque transferred through a plurality of rotating bodies, which include a plurality of surfaces that, when mechanically connected by a roller assembly, can transfer torque at an almost infinite number of gear ratios. Although a CVT can not use toothed gears per se, one of ordinary skill in the art will appreciate that the term "gear ratio" means the ratio of the radius of the driving assembly to the radius of the driven rotating assembly, which ratio directly affects the transfer of torque between the rotating assemblies. One of ordinary skill in the art will also appreciate that the electric machines powering system 100, such as electric machine 104, can operate at a constant or near constant revolutions per minute (RPM) at their rotor shafts, and CVT 112 allows for an infinite number of gear ratios, thereby varying the speed and torque transmitted through the system to the final output assembly.

[0033] Although various embodiments of CVT 112 will be discussed in greater detail below, CVT 112 can embody a plurality of types of CVTs. One of ordinary skill in the art, after reviewing this disclosure, will appreciate that any transmission system can be configured for use with a system as described herein. For example, without departing from the scope of this disclosure, a standard transmission with a different set of driven and driving gears with gear ratios can be utilized. In various embodiments, CVT 112 can be replaced or used with any assembly configured to transfer power from one assembly to another. The transmission can use one or more gears that mesh together with a plurality of diameter ratios. The transmission can use one or more lubrication systems and control systems consistent with the entire disclosure. Any number of transmissions can be deployed in the systems disclosed herein, including transmissions configured for use with a constant speed electric machine as described above.

[0034] In various embodiments, CVT 112 can be a pulley-based CVT. A pulley-based CVT can use a belt, such as a V-belt, that runs between multiple (typically two) variable-diameter pulleys. In embodiments, the pulleys can be configured to each have two tapered components, with the narrow end of each tapered component seated next to the other tapered component, with both tapered components fixedly attached to a shaft between them, with the shaft seated through the center of each tapered component. The space between the two tapered components can act as a sheave. For the purposes of this disclosure, a "sheave" is a pulley used to hold a belt, wire, rope, wire rope, or other suitable component incorporated into the pulley. The sheave can have a grooved surface. There can be a valley-like surface between the two tapered halves of the sheave. The sheave can also include an adjustable operating diameter (radius) for use with a belt, such as a V-belt.

[0035] The two tapered components can be configured to move relative to each other, thereby changing the distance between them. In various embodiments, one of the two tapered components is fixed in its position along the shaft, and the second tapered component is configured to be passively or actively actuated along the shaft. In various embodiments, both of the two tapered components can be configured to move along the shaft, thereby changing the distance between them. In various embodiments, the shaft itself can be configured to telescopically or otherwise change its length, thereby changing the relative distance of the tapered components. In various embodiments, a V-belt runs between the tapered components, contacting each tapered component, such that the effective radius of the pulley is the distance between the V-belt and the center of the shaft, though there is no pulley of precise radius. A pulley-based CVT will include another tapered half-pulley, such that changing the radius of one of the two pulleys forces a change in the radius of the other pulley (as the V-belt has a constant length).

[0036] The radial thickness of the belt is a trade-off between the largest gear ratio and the torque. Steel-reinforced V-belts are sufficient for low mass, low torque applications such as utility vehicles and snowmobiles, but high mass and high torque applications such as cars require chains. Each element of a chain must have a tapered side that fits the pulley when the belt is running at the outermost radius. As the chain moves into the pulley, the contact area gets smaller. Since the contact area is proportional to the number of elements, chain belts require many very small elements. Some CVTs transfer power to the output pulley via tension in the belt ("pull" force), while others use compression of the chain elements (where the input pulley "pushes" the belt, which in turn pushes the output pulley). Positively Infinitely Variable (PIV) chain drives differ in that the chain interlocks with the tapered pulleys. This is accomplished by having a stack of many small rectangular plates in each link that can independently slide from one side to the other. The tapered pulleys have radial grooves. The grooves on one side of the pulley meet the ridges on the other side, and so the sliding plates are pushed back and forth to conform to the pattern, effectively forming the correct pitch of teeth when squeezed between the pulleys. This type of drive can transfer a lot of torque due to the interlocking surfaces, and so is widely used in industrial applications. One tapered assembly can be fixed to the splitter output shaft, and the other tapered assembly can be fixed to the transmission shaft, thereby varying the gear ratio between the input and output shafts of the CVT 112.

[0037] In various embodiments, the CVT 112 can be a ratcheting CVT. Ratcheting CVTs can use a series of one-way clutches or ratchets that only correct and add to forward motion. The on-off nature of a typical ratchet means that many such designs are not continuous in operation (i.e., technically not a CVT), but in practice there are many similarities in operation, and a ratcheting CVT is able to produce zero output speed from any given input speed (according to the infinitely variable definition). The drive ratio is adjusted by changing the linkage geometry within the oscillating elements, so that even if the average linkage speed remains constant, the overall maximum linkage speed can be adjusted. Ratcheting CVTs can transfer a lot of torque because their static friction effectively increases with respect to torque throughput, so slippage is not possible in a reasonably designed system.

[0038] In various embodiments, CVT 112 can be a hydrostatic and / or hydraulic CVT. In various embodiments, CVT 112 can be an electric CVT. An electric CVT can include a power source, a generator, an electric motor, and a battery. The input shaft of the CVT can operate to drive the electric motor to drive the output shaft (such as a driveshaft) at a particular rpm, and excess energy can be stored by the battery. In various embodiments, CVT 112 can be a conical CVT. A conical CVT can change the transmission (gear) ratio by moving one or more rollers or belts along the axis of rotation of one or more conical rollers. In various embodiments, there can be multiple input cones in contact with an output cone, the multiple cones being directly or indirectly fixed to the input shaft. In various embodiments, the CVT can be another type of CVT not described herein, or a combination of CVTs as described herein. In various embodiments, CVT 112 can be a toroidal CVT, exemplary embodiments of which are shown in Figure 3

[0039] With continued reference to Figure 1 , system 100 includes at least one bevel gear box 116. In some embodiments, system 100 includes multiple bevel gear boxes 116. In various embodiments, there is one bevel gear box 116 for each of the driveshafts extending from each of the CVTs 112 disposed within system 100. Each bevel gear box 116 includes a bevel gear box input shaft disposed parallel to the driveshaft mechanically coupled thereto. In some embodiments, the bevel gear box input shaft can be directly coupled to the driveshaft. In some embodiments, the driveshaft and the bevel gear box input shaft are disposed in a horizontal plane. In some embodiments, the driveshaft and the bevel gear box input shaft are mechanically coupled via an intermediate assembly, such as an intermediate gear box, such that torque from the driveshaft is indirectly transferred to the bevel gear box input shaft. Bevel gear box 116 can include one or more bevel gears fixedly attached to the end of the bevel gear box input shaft. In various embodiments, bevel gear box 116 includes a housing configured to cover the meshing gears and provide bearing locations to support the bevel gear box input shaft and the bevel gear box output shaft. In various embodiments, bevel gear box 116 can include a substantially “L” shaped housing, with the bevel gear box input shaft and the bevel gear box output shaft disposed at 90 degrees to each other in the same plane, terminating within the bevel gear box 116 housing.

[0040] ​In various embodiments, the bevel gear box 116 transmits torque from the bevel gear box input shaft to the bevel gear box output shaft, thereby rotating and transmitting the direction of rotation of the output shaft. In various embodiments, the bevel gear box 116 is configured to house torque from the propeller shaft into the bevel gear box input shaft, which is disposed substantially in a horizontal plane. The bevel gear box output shaft transmits torque from the input shaft to the output shaft such that the bevel gear box output shaft rotates about an axis that is disposed at an angle compared to the horizontal plane. In various embodiments, the bevel gear box output shaft is disposed orthogonally to the horizontal plane. In various embodiments, the bevel gear box output shaft is disposed at an acute angle to the horizontal plane. In various embodiments, the bevel gear box output shaft is disposed at an obtuse angle to the horizontal plane.

[0041] A bevel gear is a gear whose shafts intersect at a variety of angles, and the teeth of the gears themselves are conical in shape. Bevel gears are most commonly mounted on shafts at 90 degrees from each other, but can be designed to work at other angles. The pitch surface of a bevel gear is a cone, known as the pitch cone. Bevel gears transmit energy from linear to perpendicular forces, making them very useful in machines that are widely used in the mechanical setup field.

[0042] Two important concepts in gear devices are the pitch surface and the pitch angle. The pitch surface of a gear is an imaginary toothless surface obtained by averaging the peaks and valleys of the individual teeth. The pitch angle of a gear is the angle between the face of the pitch surface and the axis.

[0043] The bevel gear box 116 can include two or more external bevel gears. This type of bevel gear is referred to as an external bevel gear because the gear teeth point outward. The pitch surfaces of the meshing external bevel gears are coaxial with the gear shafts; the apexes of the two surfaces are located at the intersection of the axis, disposed near the corner of the "L" shaped bevel gear box housing 116. In various embodiments, the bevel gear box 116 includes a crown gear. Bevel gears with a pitch surface angle of exactly 90 degrees have teeth that point outward, parallel to the axis, and resemble the points on a crown. In various embodiments, the bevel gear box 116 includes an equi- radial bevel gear. An equi-radial bevel gear is a special case of a bevel gear that has an equal number of teeth. The shafts are positioned at right angles to each other, and the gears have matching pitch surfaces and pitch angles, with a conical pitch surface. The cylindrical gear tooth profile corresponds to a involute (i.e., a triangular wave projected on the circumference of a circle), while the bevel gear tooth profile is an octoid (i.e., a triangular wave projected on the normal path of a circle of a sphere). In various embodiments, the bevel gear box 116 includes a spiral bevel gear. The teeth of a spiral bevel gear are formed along a spiral line. The advantage of spiral teeth over straight teeth is that they mesh more gradually. The contact between the teeth starts at one end of the gear and then spreads to the entire tooth. In this way, the transfer of force is not as abrupt when a new pair of teeth comes into play. With straight bevel gears, the abrupt meshing of the teeth can cause noise, especially at high speeds, and can put impact stress on the teeth, making them unable to withstand heavy loads at high speeds without breaking.

[0044] With continued reference to Figure 1 , the system 100 includes at least one propeller 120. In various embodiments, the propeller is coupled to the bevel gear box output shaft. In various embodiments, the system 100 includes three or more propellers. In various embodiments, the system 100 includes four propellers, disposed radially and equidistantly around the central portion of the system. In various embodiments, the four propellers are disposed at the end of a substantial amount of arm extending from the central portion of the system. The propeller 120 can be disposed substantially parallel to a horizontal plane. For the purposes of this disclosure, a "propeller" is an assembly that includes a central hub to which radially extending blades are attached, configured to produce linear lift when rotated through a fluid, such as air, in embodiments. The propeller 120 can be a fixed-pitch propeller. In various embodiments, the propeller 120 can be a variable-pitch propeller.

[0045] With continued reference to Figure 1 , the system 100 includes a flight controller 124. The flight controller 124 can be disposed proximate to the central portion of the system 100. The flight controller can include a housing, which can be air-tight and / or water-tight. The housing can be sealable to prevent dust or moisture from entering. The flight controller 124 can be configured to, as Figure 1and / or the flight controller in 4. The flight controller 124 can be one or more printed circuit boards (PCBs). The flight controller 124 can be one or more computers running concurrently on the system 100. In various embodiments, the flight controller 124 can be one or more single-board computers, such as a Raspberry Pi®, BeagleBone®, etc. The flight controller 124 can be communicatively connected to one or more sensors configured to detect data for the aircraft, the environment, health, telemetry, and other data for controlling the aircraft on which the system 100 is deployed.

[0046] For example, but not by way of limitation, the motor 104 can be housed within a drone body, such as drone body 128. The drone body 128 can be configured as a circle, an ellipse, a rectangle, a half-rectangle, or other three-dimensional polygonal body. The drone body 128 can be configured to house components of the system 100, such as the motor 104 and other centrally located or relatively heavy components, such as the shunt gear box 108. The drone body 128 can be configured to house any electronics, such as flight controllers or other wiring, transceivers, sensors, etc. The drone body 128 can be configured to include legs for landing on flat or uneven surfaces. The drone body 128 can be configured to include wheels. The drone body 128 can be formed of one or more plastics, composites, metals, or combinations thereof.

[0047] The drone body 128 can include one or more arms. For the purposes of this disclosure, an "arm" refers to a radially extending spar on which a propeller is mounted. The drone body 128 can include two arms 132, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or more arms 132. Each arm 132 can include one or more propellers 120, as will be discussed further below.

[0048] Reference is now made to Figure 2 which shows a cross-sectional view of a portion of a multi-copter drone 200 implemented using the system 100 and an embodiment of the system. It should be noted that Figure 2is a cross-sectional view of the center portion of a drone and one of its arms. In various embodiments, drone 200 may include three, four, five, six, seven, eight, nine, ten, or more arms, consistent with the description of one arm herein. Those skilled in the art will appreciate that the multiple arms that may be present in drone 200 may correspond to splitter gearbox 108. Similarly, the configuration of various components within an arm, such as size and location, may be rearranged as needed, such as to reduce arm thickness and provide a more aerodynamic profile. In various embodiments, splitter gearbox 108 may include one splitter output shaft for each arm. Those skilled in the art will appreciate that drone 200 may include only one motor 104 and one splitter gearbox 108, but other arrangements of centrally located components may also be suitable. Multicopter drone 200 may include any of the components, systems, elements, and methods described herein. For example, but not limited to, drone 200 may include motor 104 as described herein. Motor 104 may be centrally located within drone body 132. The motor 104 may be a relatively heavy component, and to balance that weight within the drone 200 , the motor 104 may be located at the radial center of the drone 200 .

[0049] Continue to refer Figure 2 , the drone 200 includes a splitter gearbox 108. The splitter gearbox 108 can be positioned at the radial center of the drone 200 and above the motor 104, thereby evenly distributing the weight of the relatively large and complex gear arrangement of the splitter gearbox 108. The splitter gearbox 108 can include one or more splitter gearbox input shafts 208 that are mechanically and rotatably coupled to the rotor shaft 204 of the motor 104. The splitter gearbox 108 can include as many splitter gearbox output shafts 212 as are required for the multiple arms present in the drone 200. The splitter gearbox output shafts 212 are mechanically and rotatably coupled to the CVT input shaft 216.

[0050] Continue to refer Figure 2 , the drone 200 includes a CVT 112 as described herein. The CVT 112 includes a drive shaft 220 rotatably coupled to a CVT input shaft 216 (as described in reference Figure 1 、 3or fully coupled to another CVT. In various embodiments, the transmission shaft 220 is disposed collinearly with the splitter gearbox output shaft 212 and the CVT input shaft 216. In various embodiments, the transmission shaft 220 is disposed non-collinearly with any other shaft herein. In various embodiments, the transmission shaft 220 is disposed radially relative to a central portion of the drone 200. In various embodiments, the transmission shaft 220 is coupled to any other component herein indirectly, such as by use of one or more intermediate gearboxes.

[0051] With continued reference to Figure 2 The drone 200 includes a bevel gearbox 116 as described herein. The bevel gearbox 116 includes a bevel gearbox input shaft 224 disposed parallel to the transmission shaft 220. The bevel gearbox input shaft 224 is rotatably directly or indirectly coupled to the transmission shaft 220. The bevel gearbox input shaft 224 can be configured to rotate about an axis that is the same or parallel to the transmission shaft 220. The bevel gearbox 116 is configured to change the direction of rotation by a system as described herein. The bevel gearbox input shaft 224 can be fixed to a first bevel gear disposed within the bevel gearbox 116. The first bevel gear can mesh with a second bevel gear. The second bevel gear is fixed to a bevel gearbox output shaft 228 disposed orthogonally and coplanar to the bevel gearbox input shaft 224. As Figure 2 As depicted, the bevel gearbox 116 can change the direction of rotation by 90 degrees. The bevel gearbox 116 can change the direction of rotation by less than 90 degrees, thereby tilting the bevel gearbox output shaft 228 toward a central portion of the drone 200. In various embodiments, the bevel gearbox 116 can change the direction of rotation by more than 90 degrees, thereby tilting the bevel gearbox output shaft 228 away from a central portion of the drone 200. In accordance with the description of Figure 1 The bevel gearbox 116 can include bevel gears adapted to the desired change in shaft direction, such as helical gears for large angles and inversely for small angles, in accordance with the description of

[0052] With continued reference to Figure 2 The drone 200 includes at least one propeller 120. The propeller 120 can be rotatably coupled to the bevel gearbox output shaft 228. The propeller 120 can be configured to rotate about the output shaft axis and provide lift via at least one blade having an airfoil cross-sectional shape.

[0053] Reference is now made to Figure 3 which shows a schematic cross-sectional view of an embodiment of the CVT 112. It will be appreciated by one of ordinary skill in the art that the CVT 112 can be any suitable type of CVT as described herein or other type of CVT not described. Figure 3A cross-sectional view of a toroidal type CVT is depicted. Toroidal CVT 300 includes an input shaft 304. Input shaft 304 can be coupled to a rotor shaft of an electric machine, which is not depicted for clarity. Input shaft 304 can be directly or indirectly coupled to a rotor shaft of electric machine 104. Input shaft 304 can be rotatably coupled to a rotor shaft of electric machine 104. Input shaft 304 includes first conical surfaces 308. First conical surfaces 308 are disposed co-linearly and radially symmetrically about input shaft 304. First conical surfaces 308 include a concave conical shape, such that the surfaces of the first conical surfaces are curved, and radially symmetric about input shaft 304.

[0054] With continued reference to Figure 3 , CVT 300 includes a drive shaft 312. According to embodiments, the drive shaft extends co-linearly with the input shaft. In various embodiments, input shaft 304 and drive shaft 312 are disposed in a non-co-linear arrangement. Drive shaft 312 includes second conical surfaces 316. Second conical surfaces 316 are disposed opposite first conical surfaces 308, with the apexes of the conical surfaces disposed proximate to one another. In embodiments, first conical surfaces 308 and second conical surfaces 316 are symmetrically disposed, and rotate about the same axis extending therebetween. In various embodiments, first conical surfaces 308 and second conical surfaces 316 include a gap therebetween. Second conical surfaces 316 include a concave conical shape, the same as or similar to the curvature of first conical surfaces 308. In various embodiments, first conical surfaces 308 and second conical surfaces 316 include different arcuate profiles.

[0055] With continued reference to Figure 3 , CVT 300 includes at least one power roller 320. Power roller 320 includes a circular surface that includes a curved edge portion configured to simultaneously contact both first conical surfaces 308 and second conical surfaces 316. Power roller 320 is configured to rotate when input shaft 308 rotates first conical surfaces 308. In turn, power roller 320 rotates second conical surfaces 316 and drive shaft 312. Power roller 320 is configured to contact both first conical surfaces 308 and second conical surfaces 316, which contact a first circumference and a second circumference, respectively, about the conical surfaces. For example, in embodiments, power roller 320 is configured to contact a first circumference of first conical surfaces 308 and a second circumference of second conical surfaces 316. In various embodiments, power roller 320 is configured to contact a first circumference of first conical surfaces 308 and a second circumference of second conical surfaces 316, which are the same or similar. Figure 3In particular embodiments, the power roller 320 is tilted such that the first circumference traced by the contact point on the first conical surface 308 is less than a second circumference traced by the power roller 320 on the second conical surface 316. The first and second circumferences can be changed by tilting the power roller 320, thereby changing the "gear ratio" between the input shaft 304 and the drive shaft 312. The power roller 320 can be tilted to contact a third circumference and a fourth circumference, thereby increasing or decreasing the infinite "gear ratio" between the input shaft 304 and the drive shaft 312. The infinite level of gear ratios that can be achieved by the CVT 300 allows the electric machine 104 to output the same RPM at the rotor shaft, but effectively control the drive shaft 312 RPM.

[0056] The power roller 320 can be tilted by an actuator, such as the actuator 324. The actuator 324 can be a stepper motor, a servo motor, or the like. The actuator 324 is configured to be controlled according to at least one of a variety of methods. In various embodiments, the actuator 324 can be controlled via an electronic signal provided by one or more flight controllers. The actuator 324 can be configured such that the flight controller controls the angular position of the servo (actuator 324), which changes the ratio contact point (i.e., the circumferences of the CVT first and second conical surfaces 308, 316, and thus its output speed).

[0057] In various embodiments, the actuator 324 can be controlled with one or more encoders, such as mechanical, optical, magnetic, electromagnetic induction, or other types of encoders. The actuator 324 is configured to rotate the power roller 320 relative to the first and second conical surfaces 308, 316, thereby changing the gear ratio between the input shaft 304 and the drive shaft 316 via the circumferences on the conical surfaces with which the power roller is in contact. The power roller 320 can include one or more tensioning components configured to maintain contact with the first and second conical surfaces 316 during high speed rotation. For example, and without limitation, the power roller 320 can include one or more biasing devices, such as leaf springs, coil springs, or the like, so as to press the power roller 320 into the first and second conical surfaces 308, 316, respectively and simultaneously. The power roller 320 can be made of one or more high friction materials to reduce or eliminate slippage against the first and second conical surfaces 308, 316.

[0058] With continued reference to Figure 3CVT 300 can include a second power roller 328. Power roller 328 can be disposed opposite power roller 320. Power rollers 320, 328 can be configured to rotate in synchronism with the other, thereby contacting the same circumference on first conical surface 308 and second conical surface 316, rotating in opposition, thereby transmitting rotation of input shaft 304 to transmission shaft 312. Second power roller 328 can be tilted via actuator 332. Actuator 332 can be a servo motor. Actuator 332 can be controlled via the same or similar command signals generated from a flight controller as described herein. Actuator 332 can be controlled via one or more onboard computers as described herein.

[0059] Reference is now made to Figure 4A , which illustrates an embodiment of a propulsion system 400 in block diagram form. One of ordinary skill in the art will appreciate that the components present in this system can be the same as or similar to the individual components described with reference to other figures of the present disclosure, i.e. Figure 1 , as described herein.

[0060] With continued reference to Figure 4A , system 400 includes electric machine 104. Electric machine 104 can be any electric machine as described herein. Electric machine 104 can be an electric motor, an internal combustion engine, a combination thereof, or other undiscussed electric machine suitable for use in system 400. Electric machine 104 can include a rotor shaft, such as rotor shaft 204. Rotor shaft 204 can be configured to transmit rotation generated by the electric machine to splitter gearbox 108.

[0061] With continued reference to Figure 4A , system 400 includes splitter gearbox 108. Splitter gearbox 108 can include one or more splitter gearbox input shafts, such as gearbox splitter input shaft 208. Splitter gearbox input shaft can be rotationally coupled to rotor shaft 204. Splitter gearbox 108 includes four splitter gearbox output shafts, similar to or the same as splitter gearbox output shafts 212. As Figure 5As shown, the splitter gearbox 108 can include four output shafts arranged radially 90 degrees apart and in the same plane as one another. The splitter gearbox outputs 108 can include four or more intermediate gearboxes or assemblies configured to transfer rotation of the rotor shafts through the input shaft of the splitter gearbox to the splitter gearbox output shafts, dividing the rotation evenly between the output shafts. Each splitter output shaft can be rotatably coupled to one of the four CVTs 112a-d. Each splitter gearbox output shaft (212) can be rotatably coupled to an input shaft of a single CVT 112a-d. Each of the CVTs 112a-d can be mounted on the splitter gearbox 108. Each CVT 112a-d can be mounted on a different face of the housing of the splitter gearbox 108. In various embodiments, the CVTs 112a-d can each include a housing configured to enclose the gearbox and provide one or more mounting portions, such as through holes, threaded holes, hooks, protrusions, etc.

[0062] With continued reference to Figure 4A , the CVTs 112a-d can be configured to adjustably transfer rotation from the splitter gearbox output shafts to the drive shafts, as described herein. The adjustable transfer of rotation is achieved by changing the contact point of one or more power rollers arranged between input and output conical surfaces attached to the input and output shafts, respectively. Each of the CVTs 112a-d can be rotatably connected to one or more servo motors (servos) 142a-d. The servos 142a-d can be configured to be independently controlled via a flight controller 124. The flight controller 124 is communicatively connected to each of the servos 142a-d and at least one command signal 136. The command signal 136 can be generated by one or more users, computers, or combinations thereof. The command signal 136 can be transmitted by one or more radio transceivers. The command signal 136 can be received by one or more remotely located receivers arranged to be communicatively coupled to the flight controller 124. The CVTs 112a-d each include at least one drive shaft extending radially therefrom. The drive shafts are each configured to variably transfer rotation from the motor 104 rotor shafts 204 to bevel gearboxes 116a-d.

[0063] With continued reference to Figure 4AThe system 400 includes four bevel gearboxes 116a-d. Each of the four bevel gearboxes 116a-d is rotatably coupled to one of the four drive shafts extending from the CVTs 112a-d, respectively. The bevel gearboxes 116a-d each include a bevel gearbox input shaft, as described herein. The input shaft is disposed in, or parallel to, a horizontal plane. The input shaft can be disposed collinearly with the drive shaft. The bevel gearboxes 116a-d can include a bevel gearbox output shaft disposed orthogonal and coplanar to the input shaft, thereby changing the direction of the shaft from substantially horizontal to substantially vertical. The bevel gearboxes 116a-d can be configured to transfer rotation of the horizontal plane in the drive shafts extending radially from the CVTs 112a-d to a vertical orientation, thereby rotating one of the fourth propellers 120a-d. In various embodiments, a first portion of the bevel gearboxes 116a-d is configured to rotate a first portion of the propellers 120a-d in a first direction, and a second portion of the gearboxes 116a-d is configured to rotate a second portion of the propellers 120a-d in a second direction, where the second direction is different from the first direction. In various embodiments, the propellers 120a, 120c are configured to rotate clockwise via the gearboxes 116a, 116c, and the propellers 120b, 120d are configured to rotate counterclockwise via the gearboxes 116b, 116d, as shown in Figure 5 Due to conservation of angular momentum, counter-rotation of successive propellers in the four-propeller system 400 prevents the drone 200 as a whole from rotating. For example, but not by way of limitation, if all of the propellers were rapidly rotating in the same direction, such as the clockwise direction, then the entire drone 200 would also rotate. It will be noted by one of ordinary skill in the art that the systems disclosed herein allow for individual control of individual propellers of the four propellers, and thus the motion of the drone 200 can be controlled with an infinite arrangement of propellers rotating at certain RPMs.

[0064] Reference is now made to Figure 4B which shows a schematic embodiment of a propulsion system. It will be appreciated by one of ordinary skill in the art that, Figure 4B the representation of the components shown in

[0065] With continued reference to Figure 4B , the system 400 includes the motor 104, here shown as an electric motor disposed at a central portion of the system, the motor 104 showing conductive windings passing through the housing. The motor 104 can be centrally positioned within the system 400 for the purpose of distributing weight, but in various embodiments can also be positioned elsewhere in the system. For example, the motor 104 can be disposed on its own arm, or within an arm of the propellers.

[0066] With continued reference to Figure 4B , the system 400 includes a splitter gearbox 108, shown as having one input shaft (as described herein) and a total of four output shafts (three visible). Rotation of the input shaft transmits torque to each of the four output shafts. In various embodiments, rotation of the input shaft can transmit torque to one or more output shafts in one or two possible rotational directions.

[0067] With continued reference to Figure 4B , the system 400 includes four CVTs 112. The four CVTs 112 can correspond to any of the CVTs 112a-d shown as Figure 4A . The four CVTs 112 are shown as toroidal CVTs as described herein, but this does not limit the type of CVT that can be used in the system 400. The CVTs 112 can include an input shaft and an output shaft that are rotatably coupled together by a torque-transferring element configured to roll with the input shaft and transfer torque to the output shaft, the angle of the torque-transferring element forming a gear ratio between the input shaft and the output shaft as described herein.

[0068] With continued reference to Figure 4B , the system 400 includes four bevel gearboxes 116 disposed at each arm of the propulsion system 400. The bevel gearboxes 116 can be configured to transfer torque from the CVT output shafts up 90 degrees to the propellers 120. The bevel gearboxes 116 can include different angles, such as an oblique angle, an acute angle, or a series of turns, configured to dispose each of the propellers 120 at an angle other than the input shaft of the bevel gearboxes 116.

[0069] With continued reference to Figure 4B , the system 400 includes four propellers 120 attached to the output shaft of each of the bevel gearboxes 120. Each of the propellers can be configured to rotate in a first direction or a second direction. For example, but not by way of limitation, two of the four propellers 120 can be configured to rotate in the first direction, and the other two propellers can be configured to rotate in the second direction. In various embodiments, the propellers 120 can be configured to arrange co-directional propellers adjacent to each other or across, as described herein. Figure 5As described herein, each of the propellers 120 can be counter-rotating propellers such that one propeller attached to an output shaft of a bevel gear box rotates in a first direction and a second propeller attached to the same output shaft and disposed concentrically with the first propeller rotates in a second direction. In various embodiments, each bevel gear box can include more than one propeller 120 attached to one or more output shafts, such as a propeller disposed on a first side of the bevel gear box and a second propeller disposed on a second side of the bevel gear box, each propeller driven by the bevel gear box via the one or more output shafts. For example, and without limitation, the propellers in the foregoing embodiments can be counter-rotating propellers or can rotate in the same direction. The effect is to cancel the rotational momentum of the propellers. In this manner, counter-rotating propellers can be disposed at each of the arms of the system 400. In various embodiments, counter-rotating propellers can be arranged at one or more arms of the system 400.

[0070] Referring now to Figure 6A- C, which shows a front isometric view of CVT 600. CVT 600 can operate similarly to CVT 300 and / or any CVT 112 as described herein. CVT 600 includes a CVT input shaft 604. CVT input shaft 604 can be rotatably coupled to one of a plurality of different splitter gearbox output shafts. CVT input shaft 604 can be coupled to the shafts by one or more interlocking features, such as a slot and tang, a keyway and slotted protrusion, etc. In various embodiments, CVT input shaft 604 can be coupled to a splitter gearbox output shaft via splines disposed along one or both shafts and a toothed collar that fixedly couples the shafts together. CVT input shaft 604 can be disposed co-linearly with one or more shafts to which it is directly or indirectly coupled. CVT input shaft 604 is coupled to an input pulley 608. Input pulley 608 can be fixedly coupled to CVT input shaft 604 and configured to rigidly rotate with the CVT input shaft 604. Input pulley 608 can be fixed to CVT input shaft 604 via one or more bearings, such as ball bearings, sleeve bearings, etc. CVT input shaft 604 can include one or more cutouts that comprise circumferentially disposed teeth configured to mate with a plurality of splines disposed on CVT input shaft 604. In various embodiments, input pulley 608 can be formed from a metal, a composite material, a plastic, etc. For example, input pulley can be formed from a variety of steel alloys. For example, input pulley 608 can be formed from aluminum. For example, input pulley 608 can be formed from an additive manufacturing technique, such as 3D printing, etc. In various embodiments, input pulley 608 can be substantially formed from a first material, such as machined aluminum, where an outermost edge of input pulley 608 can be formed from, or include, rubber applied thereon. Rubber disposed on an edge of input pulley 608 can be configured to prevent slippage between the pulley and a rotating component in contact therewith.

[0071] With continued reference to Figure 6A-C, the CVT 600 includes a driveshaft 612. The driveshaft 612 can be the same as or similar to any driveshaft as described herein. The driveshaft 612 can be fixedly coupled to an output wheel 616. The driveshaft 612 and the output wheel 616 can be configured to rotate at the same rate. In various embodiments, the driveshaft 612 can be configured to rotate at a rate different from the rate of the output wheel 616, the two components being indirectly connected through an intermediate gear box as described herein. The output wheel 616 is disposed opposite and face-to-face with the input wheel 608, the input shaft 604 and the driveshaft 612 can be disposed collinearly. The output wheel 616 can be formed in the same or similar manner as the input wheel 608. The output wheel 616 can be fixed to the driveshaft 612 in the same or similar manner as the input wheel 608 is fixed to the input shaft 604. The output wheel 616 and the input wheel 608 can be substantially parallel and configured to rotate in planes parallel to each other. The output wheel 616 and the input wheel 608 define a space therebetween, the space spanning the distance of the outermost edges of the input wheel 608 and the output wheel 616. In various embodiments, each of the input wheel 608 and the output wheel 616 includes at least one tensioning component (not pictured). The tensioning component can be configured to align and support one or both of the input wheel 608 and the output wheel 616 during rotation thereof, and / or to counteract possible deflection caused by forces exerted on the wheels by the TTC 620. The one or more tensioning components can be configured to maintain a suitable spacing between the input wheel 608 and the output wheel 616. The one or more tensioning components can include one or more springs, such as coil springs, leaf springs, radial springs, or combinations thereof. The one or more tensioning components can include one or more bearings, such as ball bearings, sleeve bearings, torsion bearings, deep groove bearings, angular contact bearings, self-aligning bearings, cylindrical bearings, full complement cylindrical roller bearings, needle bearings, tapered bearings, and the like.

[0072] With continued reference to Figure 6A-C, CVT 600 includes a torque transfer component (TTC) 620. TTC 620 is at least partially rotatably disposed between input wheel 608 and output wheel 616. TTC 620 can be disposed proximate the edges of input wheel 608 and output wheel 616. In various embodiments, TTC 620 can be disposed proximate the rotational axis of one or both of input wheel 608 and output wheel 616. In various embodiments, TTC 620 can be disposed at the outermost edges of input wheel 608 and output wheel 616. TTC 620 is configured to simultaneously contact a portion of input wheel 608 and output wheel 616. TTC 620 can be configured to simultaneously contact equal sized portions of input wheel 608 and output wheel 616. TTC 620 can be configured to simultaneously and separately contact differently sized portions of input wheel 608 and output wheel 616. TTC 620 can be configured to contact different portions of each of input wheel 608 and output wheel 616 over time. In various embodiments, TTC 620 can be formed of metal, composite material, plastic, or combinations thereof.

[0073] Still referring to Figure 6A -C, TTC 620 can form at least a portion of a spherical profile. In various embodiments, TTC 620 is hemispherical, with the apex of the hemisphere disposed toward the space of input wheel 608 and output wheel 616. In various embodiments, TTC 620 includes a full or partial sphere, where the equidistant radius defining the sphere extends through a midpoint where the hemisphere would terminate. In various embodiments, TTC 620 is an elliptically curved shape that surrounds Figure 6A is radially symmetric about a vertical axis through its center (only shown for orientation, axis not included for clarity). In various embodiments, TTC 620 is a three-dimensional shape that includes multiple arcs, rather than just a continuous arcuate surface as found in a sphere. In various embodiments, TTC 620 is another radially symmetric shape, with a substantially circular cross-section, configured to rotate under the frictional force of input wheel 608. In various embodiments, TTC 620 is formed of rubber or other non-slip material, configured to create suitable friction between input wheel 608, TTC 620, and output wheel 616 in turn.

[0074] Continuing to refer to Figure 6A-C, TTC 620 is configured to tilt along an arcuate path within the space between input wheel 608 and output wheel 616. TTC 620 can be configured to tilt in a direction parallel to input shaft 604 and drive shaft 612. Tilting of TTC 620 in turn changes the circumference of the profile that contacts both input wheel 608 and output wheel 616. For example, but not by way of limitation, when TTC 620 is in a "direct drive" position, TTC 620 is oriented substantially parallel to the wheels. As a result, the circumference of the spherical profile of TTC 620 that contacts both input wheel and output wheel 616 is the same. As TTC 620 tilts toward one of the wheels, the circumference in the direction of the tilt increases, and the circumference of the wheel in the opposite direction of the tilt decreases. Since input wheel 608 rotates TTC 620, and TTC 620 in turn rotates output wheel 616, the effective gear ratio between the input wheel and the output wheel changes as a result of the different circumferences of each of the wheels on TTC 620. In various embodiments, the profile of TTC 620 can be configured such that the circumference of the wheel in the direction of the tilt of TTC 620 decreases, and the circumference of the opposite wheel increases. Those skilled in the art will appreciate that the profile of TTC 620, as well as the shape and size of each of input wheel 608 and output wheel 616, can be configured to manipulate the effective gear ratio to change as a function of the tilt of TTC 620.

[0075] With continued reference to Figure 6A -C, TTC 620 can be mounted on a rotatable mounting arm (RTA) 624. RTA 624 can be disposed generally around the circumference of one side of input wheel 608 and output wheel 616, as shown in Figure 6A -B. RTA 624 can be configured to suspend TTC 620 in an optimal position relative to the wheels. RTA 624 can be rotated as a unit, thereby tilting the spherical portion of TTC 620 relative to the edges of input wheel 608 and output wheel 616. RTA 624 can be coupled to an actuator, such as actuator 628. Actuator 628 can be a servo motor, such as Figure 6A -B. Actuator 628 can be a stepper motor. Actuator 628, as well as any actuators as described herein, can be controlled by one or more computers, such as a flight controller consistent with the description herein. In various embodiments, actuator 628, as well as any actuators as described herein, are controlled by a flight controller via a pulse width modulation (PWM) signal.

[0076] With specific reference now to Figure 6BCVT 600 can include a tensioning assembly 632 configured to bias the TTC 620 against both the input wheel 608 and the output wheel 616 simultaneously. The tensioning assembly 632 can be located inside the column connecting the spherical portion of the TTC 620 and the RTA 624. The tensioning assembly 632 can be a coil spring, with a first end of the spring seated at the inside of the spherical assembly and a second end of the spring seated at the RTA 624, with tension in the spring used to extend the spherical portion away from the RTA 624, thereby simultaneously pressing the spherical portion against both the input wheel 608 and the output wheel 616. When the RTA 624 rotates, the tensioning assembly 632 can expand or contract in order to contact the input wheel 608 and the output wheel 616 throughout the rotation of the RTA 624, specifically, throughout the arc of rotation of the spherical portion of the TTC 620.

[0077] With specific reference to Figure 6C The CVT 600 includes a CVT housing 636. The CVT housing 636 can be formed from plastic, metal, composite material, or the like. The housing 636 can be configured to prevent dust and contaminants from entering into contact surfaces of the components of the CVT 600. The CVT housing 636 can be fastened closed via one or more mechanical fasteners, such as screws, nails, pegs, and necessary holes for their use. The CVT housing 636 can include hardware configured to mount the CVT 600 to one or more portions of the system 400, such as to one or more portions of the shunt gearbox 108, for example, the housing thereof.

[0078] Referring now to Figure 7 which shows a schematic diagram of an example of a computing node. The computing node 710 is but one example of a suitable computing node and is not intended to suggest any limitation as to the scope of use or functionality of embodiments described herein. Regardless, the computing node 710 is capable of being implemented and / or performing any of the functionality set forth above.

[0079] Within the computing node 710 there is a computer system / server 712, which is operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well- known computing systems, environments, and / or configurations that can be suitable for use with computer system / server 712 include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices, and the like.

[0080] The computer system / server 712 can be described in the general context of computer system-executable instructions, such as program modules, being executed by a computer system. Generally, program modules can include routines, programs, objects, components, logic, data structures, and so on that perform particular tasks or implement particular abstract data types. Computer system / server 712 can be practiced in distributed cloud computing environments with remote processing devices that are coupled over a communications network. In a distributed cloud computing environment, program modules can be located in both local and remote computer system storage media including memory storage devices.

[0081] As shown Figure 7 The computer system / server 712 in computing node 710 is shown in the form of a general-purpose computing device. The components of computer system / server 712 can include, but are not limited to, one or more processors or processing units 716, a system memory 728, and a bus 718 that couples various system components including system memory 728 to processor 716.

[0082] Bus 718 represents one or more of any of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, Peripheral Component Interconnect (PCI) bus, PCI Express (Pie) and Advanced Microcontroller Bus Architecture (AMBA) O

[0083] Computer system / server 712 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by computer system / server 712 and includes both volatile and non-volatile media, removable and non-removable media.

[0084] The system memory 728 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 730 and / or cache memory 732. The computer system / server 712 can further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, a storage system 734 can be provided for reading from and writing to non-removable, non-volatile magnetic media (not shown and typically called a "hard drive"). Although not specifically shown, a magnetic disk drive can also be used for reading and writing to a removable, non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive can be used for reading from or writing to a removable, non-volatile optical disk (such as a CD-ROM, DVD-ROM or other optical media). In such instances, each drive can be connected to the bus 718 by one or more data media interfaces. As will be further depicted and described below, the memory 728 can include at least one program product having a set (e.g., at least one of the program modules) of program modules configured to carry out the functions of embodiments of the disclosure.

[0085] The program / utility 740 having a set (at least one of the program modules) of program modules 742 can be stored in memory 728 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data. Each of the operating system, one or more application programs, other program modules, and program data or some combination thereof, can include an implementation of a networking environment. The program modules 742 commonly perform the functions and / or methodologies described herein as embodiments of the disclosure.

[0086] The computer system / server 712 can also communicate with one or more external devices 714 such as a keyboard, a pointing device, a display 724, etc.; one or more devices that enable a user to interact with the computer system / server 712; and / or any devices (e.g., network card, modem, etc.) that enable the computer system / server 712 to communicate with one or more other computing devices. Such communication can occur via Input / Output (I / O) interfaces 722. Still yet, the computer system / server 712 can communicate with one or more networks such as a local area network (LAN), a general wide area network (WAN), and / or a public network (e.g., the Internet) via network adapter 720. As depicted, network adapter 720 communicates with the other components of the computer system / server 712 via bus 718. It should be understood that although not shown, other hardware and / or software components could be used in conjunction with the computer system / server 712. Examples include, but are not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0087] The present disclosure can be implemented as a system, a method, and / or a computer program product. The computer program product can include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure.

[0088] The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium can be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

[0089] Computer readable program instructions described herein can be downloaded to respective computing / processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and / or a wireless network. The network can comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and / or edge servers. A network adapter card or network interface in each computing / processing device receives computer readable program instructions from the network and forwards the computer readable program instructions to storage media within the respective computing / processing device for execution by a processor.

[0090] Computer readable program instructions for carrying out operations of the present disclosure can be in assembly code, instruction set architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program instructions can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) can execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure.

[0091] Aspects of the present disclosure are described herein with reference to flowcharts and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present disclosure. It will be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer readable program instructions.

[0092] These computer readable program instructions can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks. These computer readable program instructions can also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and / or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0093] The computer readable program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus implement the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0094] The flowchart and block diagram in the drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams can represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations thereof, can be implemented by a dedicated hardware-based system that performs the specified functions or acts or combinations of special-purpose hardware and computer instructions.

[0095] The description of various embodiments of the present disclosure is presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A propulsion system, comprising: an electric machine positioned at the first portion of the propulsion system, the electric machine further comprising a rotor shaft; a splitter gearbox coupled to the rotor shaft, the splitter gearbox further comprising at least one splitter output shaft; at least one continuously variable transmission (CVT) coupled to the splitter output shaft, the CVT further comprising a drive shaft; at least one bevel gearbox, the bevel gearbox comprising a bevel gearbox input shaft and a bevel gearbox output shaft, the bevel gearbox input shaft being arranged parallel to a horizontal plane, and the bevel gearbox output shaft being arranged at an angle to the bevel gearbox input shaft, and The bevel gearbox input shaft is coupled to the transmission shaft; as well as At least one propeller is coupled to the bevel gearbox output shaft.

2. The propulsion system of claim 1 , wherein the CVT comprises: an input shaft coupled to an output shaft of the electric machine, the input shaft including a first tapered surface comprising a concave tapered shape that is co-linear with the input shaft; a second tapered surface coupled to the drive shaft, the second tapered surface comprising a concave tapered shape co-linear with the drive shaft, the second tapered surface being positioned opposite the first tapered surface; at least one powered roller comprising a circular surface rotatably disposed between the first tapered surface and the second tapered surface, the powered roller being configured to contact the first tapered surface and the second tapered surface at a first circumference and a second circumference, respectively, wherein: The powered roller is configured to rotate while in contact with the first tapered surface and the second tapered surface at the first circumference and the second circumference, respectively.

3. The propulsion system of claim 2, wherein the power roller is rotatably disposed between the first tapered surface and the second tapered surface and is configured to rotate thereby contacting a third circumference and a fourth circumference, respectively.

4. The propulsion system of claim 2, wherein the powered roller is coupled to an actuator configured to rotate the powered roller between the first and second circumferences and the third and fourth circumferences.

5. The propulsion system of claim 4, wherein the actuator is a servo motor.

6. The propulsion system of claim 1 , wherein the CVT comprises: an input shaft coupled to an input wheel, the input wheel being configured to rotate together with the input shaft; an output wheel coupled to the transmission shaft, the output wheel being configured to rotate together with the transmission shaft, the output wheel being disposed parallel to and facing the input wheel such that a spacing is defined between the output wheel and the input wheel; a torque transfer assembly rotatably disposed between the input wheel and the output wheel, the torque transfer assembly comprising at least a portion of a spherical profile configured to tangentially contact the input wheel and the output wheel simultaneously, and wherein The torque transmitting assembly is configured to tilt along an arcuate path within the spacing between the input wheel and the output wheel.

7. The propulsion system of claim 6, wherein the torque transfer assembly is coupled to a rotatable mounting arm, the rotatable mounting arm being further coupled to an actuator configured to tilt the rotatable mounting arm.

8. The propulsion system of claim 7, wherein the rotatable mounting arm includes a tensioning assembly configured to bias the torque transfer assembly against both the input wheel and the output wheel.

9. The propulsion system of claim 8, wherein the actuator is a servo motor.

10. The propulsion system of claim 6, wherein each of the input wheel and the output wheel includes a wheel tensioner assembly configured to maintain the spacing between the input wheel and the output wheel.

11. The propulsion system of claim 1 , wherein the electric machine is an electric motor.

12. The propulsion system of claim 1, wherein the electric machine is an internal combustion engine.

13. The propulsion system of claim 1, wherein the propulsion system comprises three or more propellers.

14. The propulsion system of claim 13, wherein the propulsion system comprises four propellers, the four propellers being radially and equidistantly positioned around a central portion of the propulsion system.

15. The propulsion system of claim 9, wherein the servo motor is controlled by a flight controller via a pulse width modulation (PWM) signal.

16. The propulsion system of claim 8, wherein the tensioning assembly is a spring.

17. A propulsion system, comprising: an electric motor positioned at a central portion of the propulsion system, the electric motor further comprising a rotor shaft; a splitter gearbox coupled to the rotor shaft, the splitter gearbox further comprising: four diverter gearbox output shafts extending radially from the diverter gearbox at 90 degree intervals, and wherein: Each of the diverter gearbox output shafts is disposed in a horizontal plane; four continuously variable transmissions (CVTs), each CVT coupled to one of the splitter gearbox output shafts, and in: Each of the CVTs is positioned adjacent to the diverter gearbox, each CVT further comprising a drive shaft, wherein Each of the four transmission shafts extends radially and respectively co-linearly with each of the diverter gearbox output shafts; four bevel gearboxes, each bevel gearbox coupled to one of the transmission shafts, the bevel gearboxes comprising a bevel gearbox input shaft and a bevel gearbox output shaft, the bevel gearbox input shaft being disposed coplanar with the diverter gearbox output shaft, and the bevel gearbox output shaft being disposed at a right angle to the gearbox input shaft; At least four propellers are each coupled to one of the bevel gearbox output shafts, each propeller being configured to rotate about each of the bevel gearbox output shafts parallel to the horizontal plane.

18. The propulsion system of claim 17, wherein a first portion of the bevel gearbox is configured to rotate a first portion of the propeller in a first direction, and a second portion of the bevel gearbox is configured to rotate a second portion of the propeller in a second direction, wherein the second direction is different from the first direction.

19. The propulsion system of claim 17, wherein each CVT is coupled to a different servo motor.

20. The propulsion system of claim 17, wherein each servo motor is configured to be independently controlled.

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