A variable-pitch propeller passively controlled by thrust.

Abstract

This relates to a variable-pitch propeller passively controlled by thrust. [Solution] The variable-pitch propeller 200 includes a plurality of control arms 260 coupled to a hub 250, a plurality of blade holders 270 coupled to the control arms 260, and a plurality of propeller blades 275. Each propeller blade 275 is coupled to one of the blade holders 270 and can rotate between a high-pitch position and a low-pitch position as a ball spline bearing 240 slides along a ball spline shaft 230. A thrust spring 220 controls the sliding of the ball spline bearing 240 along the ball spline shaft 230 based on the amount of thrust provided by the variable-pitch propeller 200, thereby automatically adjusting the pitch position of the propeller blades 275 based on the amount of thrust.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to propellers, and more specifically, to variable-pitch propellers that are passively controlled by thrust. BACKGROUND ART

[0002] Vertical takeoff and landing (VTOL) aircraft are capable of both horizontal cruise flight and vertical / hovering flight. As an example, electric fixed-wing VTOL unmanned aerial vehicles (UAVs) may include one or more propellers that vary in tilt to support both vertical and horizontal flight modes. As another example, tailsitter type aircraft may include one or more propellers at the tail that allow the aircraft to take off and land vertically in addition to normal horizontal flight. In these and other aircraft where the same propeller is used in both vertical and horizontal flight modes, it is typically desirable to utilize different propeller blade pitches for different flight modes. For example, hovering and vertical flight typically require smaller propeller blade pitches, while fixed-wing horizontal flight typically requires larger propeller blade pitches. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEMS

[0003] In some embodiments, the aircraft includes a fixed wing, a motor, and a variable-pitch propeller coupled to the motor. The variable-pitch propeller includes a shaft, a hub configured to slide along the shaft, and a plurality of propeller blades. Each propeller blade is coupled to the hub and configured to rotate between a high-pitch position and a low-pitch position as the hub slides along the shaft. The variable-pitch propeller further includes a thrust spring mounted around the shaft. The thrust spring is configured to control the sliding of the hub along the shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust.

[0004] In some embodiments, a variable-pitch propeller includes a ball spline shaft, a collet coupled near one end of the ball spline shaft, and a ball spline bearing configured to slide along the ball spline shaft. The variable-pitch propeller further includes a thrust spring positioned around the ball spline shaft between the collet and the ball spline bearing, a base mounting plate coupled to the ball spline shaft on the opposite side of the ball spline bearing from the thrust spring, a hub coupled to the ball spline bearing, and a plurality of control arms. Each control arm is coupled to the hub and the base mounting plate. The variable-pitch propeller further includes a plurality of blade holders and a plurality of propeller blades. Each blade holder is coupled to one of the control arms, and each propeller blade is coupled to one of the blade holders. Each propeller blade is configured to rotate between a high-pitch position and a low-pitch position as the ball spline bearing slides along the ball spline shaft. The thrust spring is configured to control the sliding of a ball spline bearing along a ball spline shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust.

[0005] In some embodiments, a variable-pitch propeller includes a ball spline shaft, a ball spline bearing configured to slide along the ball spline shaft, and a thrust spring mounted around the ball spline shaft. The variable-pitch propeller further includes a hub coupled to or integrated with the ball spline bearing, a plurality of control arms coupled to the hub, a plurality of blade holders coupled to the control arms, and a plurality of propeller blades. Each propeller blade is coupled to one of the blade holders and can rotate between a high-pitch position and a low-pitch position as the ball spline bearing slides along the ball spline shaft. The thrust spring controls the sliding of the ball spline bearing along the ball spline shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust.

[0006] A technical advantage of a particular embodiment is the provision of a thrust-controlled variable-pitch propeller that automatically adjusts the pitch position of the propeller blades based on the amount of thrust. Instead of using actuators and / or computer controllers to adjust the pitch position of the propeller blades, as may be used in existing aircraft, embodiments of the present disclosure utilize only a mechanical mechanism to automatically adjust the pitch position of the propeller blades based on the amount of thrust of the propeller. By automatically adjusting the pitch position of the propeller blades based on the amount of thrust, instead of requiring heavy or complex mechanisms to adjust the pitch position of the propeller blades, the thrust-controlled variable-pitch propellers of the disclosed embodiments can be used in both vertical and horizontal flight modes in aircraft such as electric VTOL UAVs.

[0007] The features and technical advantages of the present invention have been outlined in a fairly general manner above to allow for a better understanding of the detailed description of the present invention described later. Additional features and advantages of the present invention that constitute the subject matter of the claims of the present invention are described below. Those skilled in the art will understand that the disclosed concepts and specific embodiments are readily available as a basis for modifying or designing other structures to achieve the same objectives of the present invention. They will also understand that such equivalent configurations do not depart from the spirit and scope of the present invention as described in the appended claims. Novel features (both relating to their configuration and operation) that are recognized as characterizing the present invention will be better understood from the following description when considered in conjunction with the appended drawings, along with further objectives and advantages. However, it should be clearly understood that each drawing is provided for illustrative and descriptive purposes only and does not define the limitations of the present invention.

[0008] To gain a more complete understanding of this disclosure and its merits, please refer to the following statement, which should be read in conjunction with the attached drawings. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram of an aircraft utilizing one or more thrust-controlled variable-pitch propellers according to a specific embodiment. [Figure 2A] A thrust-controlled variable-pitch propeller, which may be used by the aircraft shown in Figure 1 according to a specific embodiment, is shown. [Figure 2B] A thrust-controlled variable-pitch propeller, which may be used by the aircraft shown in Figure 1 according to a specific embodiment, is shown. [Figure 3A] Figures 2A and 2B show the blade pitch of a thrust-controlled variable-pitch propeller according to a specific embodiment. [Figure 3B] Figures 2A and 2B show the blade pitch of a thrust-controlled variable-pitch propeller according to a specific embodiment. [Figure 4] Figures 2A-2B show a spinner that can be used with a thrust-controlled variable-pitch propeller according to a specific embodiment. [Figure 5] Figures 2A-2B show a ball spline bearing that may be used in a thrust-controlled variable-pitch propeller according to a specific embodiment. [Figure 6A] The blade hubs shown in Figures 2A-2B may be used by thrust-controlled variable-pitch propellers according to a specific embodiment. [Figure 6B] The blade hubs shown in Figures 2A-2B may be used by thrust-controlled variable-pitch propellers according to a specific embodiment. [Figure 7] Figures 2A-2B show a base mounting plate that may be used with the thrust-controlled variable-pitch propeller according to a specific embodiment. [Figure 8] Another thrust-controlled variable-pitch propeller, which may be used by the aircraft in Figure 1 according to a specific embodiment, is shown. [Modes for carrying out the invention]

[0010] It should be understood that drawings are not necessarily drawn to actual size, and that disclosed embodiments may be shown as schematic or partial drawings. In certain examples, details that are unnecessary for understanding the disclosed method and apparatus, or that make it difficult to recognize other details, may be omitted. Naturally, it should be understood that this disclosure is not limited to the specific embodiments shown herein.

[0011] The disclosures presented in the following description, and their various features and advantageous details, are more fully described by reference to the non-limiting examples included in the accompanying drawings and detailed herein. Descriptions of well-known components have been omitted so as not to unnecessarily obscure the main features described herein. The examples used herein are intended to facilitate understanding of how the disclosures may be implemented and practiced. A person skilled in the art will understand this disclosure to mean that any suitable combination of the following functionalities or exemplary embodiments can be combined to achieve the claimed subject matter. This disclosure includes a representative number of species belonging to the genus, or structural features common to members of the genus so that a person skilled in the art can recognize members of the genus. Therefore, these examples should not be construed as limiting the scope of the claims.

[0012] A person skilled in the art will understand that every system claim presented herein includes all the elements and limitations disclosed herein, and therefore requires each system claim to be viewed as a whole. Any reasonably foreseeable matters functionally related to the claims are also relevant. The examiner, having fully understood the disclosures and claims of this application, has searched the prior art disclosed in patents and other published documents (i.e., non-patent literature). Thus, as demonstrated by the issuance of this patent, the prior art neither discloses nor teaches the elements and limitations presented in the claims that are achievable herein and in the drawings, and consequently the presented claims are patentable under the applicable laws and rules of this jurisdiction.

[0013] Vertical take-off and landing (VTOL) aircraft are capable of both horizontal cruising and vertical / hovering flight. For example, an electric fixed-wing VTOL unmanned aerial vehicle (UAV) may include one or more propellers with varying inclination to support both vertical and horizontal flight modes. Another example is a tail-sitter aircraft, which may include one or more propellers at the tail to enable vertical take-off and landing in addition to normal horizontal flight. In these and other aircraft where the same propellers are used in both vertical and horizontal flight modes, it is generally desirable to utilize different propeller blade pitches for the different flight modes. For example, hovering and vertical flight typically require a smaller propeller blade pitch, while horizontal flight with fixed wings typically requires a larger propeller blade pitch.

[0014] To address these and other issues relating to aircraft that utilize the same propeller for both vertical and horizontal flight modes, the disclosed embodiments provide a thrust-controlled variable-pitch propeller that autonomously and automatically adjusts the pitch position of the propeller blades based on the amount of thrust. Instead of using actuators and / or computer controllers to adjust the pitch position of the propeller blades, as is common in some existing aircraft, embodiments of the present disclosure simply utilize a mechanical mechanism that automatically adjusts the pitch position of the propeller blades based on the amount of thrust of the propeller. More specifically, embodiments of the present disclosure utilize a blade hub that can slide along a ball spline shaft. A control arm is coupled to the blade hub, causing the propeller blades to rotate and change their pitch position as the blade hub slides along the ball spline shaft. A thrust spring is installed around the ball spline shaft to control the sliding of the blade hub along the ball spline shaft based on the amount of thrust provided by the variable-pitch propeller, thereby autonomously and automatically adjusting the pitch position of the propeller blades based on the amount of thrust. As a result, thrust-controlled variable-pitch propellers can be used in both vertical and horizontal flight modes in aircraft such as electric VTOL UAVs without requiring heavy or complex mechanisms to adjust the pitch position of the propeller blades.

[0015] Figure 1 shows an aircraft 100 according to a particular embodiment. In some embodiments, the aircraft 100 includes a fixed wing 110, one or more motors 120, and thrust-controlled variable-pitch propellers 130 coupled to one or more motors 120. In some embodiments, the aircraft 100 includes two motors 120 and two thrust-controlled variable-pitch propellers 130 as shown. In some embodiments, the aircraft 100 may include any suitable number of motors 120 and thrust-controlled variable-pitch propellers 130. The aircraft 100 can be any suitable aircraft with any suitable configuration. For example, the aircraft 100 can be a VTOL aircraft or a non-VTOL aircraft, an electric or non-electric aircraft (for example, the motors 120 can be electric or non-electric), a manned or unmanned aircraft, a tailsitter aircraft, or any combination of these aircraft. In a particular embodiment, the aircraft 100 can be an electric VTOL UAV. In some embodiments, the motor 120 and the thrust-controlled variable-pitch propeller 130 are configured to rotate between a vertical flight position and a horizontal flight position.

[0016] Generally, aircraft 100 utilizes thrust-controlled variable-pitch propellers 130 for both horizontal and vertical flight. To optimize the performance of aircraft 100 in these two flight modes (e.g., to reduce power consumption of aircraft 100, to improve flight performance of aircraft 100, etc.), the pitch of the propeller blades of the thrust-controlled variable-pitch propellers 130 is autonomously and automatically adjusted for each flight mode. For example, in the case of horizontal flight (e.g., fixed-wing cruising flight), the propeller blades of the thrust-controlled variable-pitch propellers 130 are automatically adjusted to have a high pitch. In the case of vertical / hovering flight, the propeller blades of the thrust-controlled variable-pitch propellers 130 are automatically adjusted to have a low pitch. However, instead of utilizing heavy and complex mechanisms (e.g., actuators and computer controllers) to adjust the pitch of the propeller blades of the thrust-controlled variable-pitch propeller 130, the thrust-controlled variable-pitch propeller 130 utilizes only mechanical mechanisms to autonomously and automatically control the pitch of the propeller blades based on the amount of thrust generated by the thrust-controlled variable-pitch propeller 130. In particular, some embodiments of the thrust-controlled variable-pitch propeller 130 utilize a blade hub that can slide along a ball spline shaft. A control arm is coupled to the blade hub, causing the propeller blades to rotate and change their pitch position as the blade hub slides along the ball spline shaft. A thrust spring is installed around the ball spline shaft to control the sliding of the blade hub along the ball spline shaft based on the amount of thrust provided by the thrust-controlled variable-pitch propeller 130, thereby autonomously and automatically adjusting the pitch position of the propeller blades based on the amount of thrust. Specific embodiments of the thrust-controlled variable-pitch propeller 130 are described in more detail below with reference to Figures 2A-7.

[0017] Figures 2A to 2B illustrate a thrust-controlled variable-pitch propeller 200 that may be utilized as the thrust-controlled variable-pitch propeller 130 by the aircraft 100 of Figure 1, in accordance with certain embodiments. Figure 2A shows the thrust-controlled variable-pitch propeller 200 with a spinner 210 installed, and Figure 2B shows the thrust-controlled variable-pitch propeller 200 with the spinner 210 removed. In some embodiments, the thrust-controlled variable-pitch propeller 200 includes a top collet 205, a thrust spring 220, a ball spline shaft 230, a ball spline bearing 240, a blade hub 250, a control arm 260, a blade holder 270, and a base mounting plate 280. Each blade holder 270 is coupled to a blade 275. The base mounting plate 280 couples the thrust-controlled variable-pitch propeller 200 to a motor 290.

[0018] In general, the pitch of the blades 275 of the thrust-controlled variable-pitch propeller 200 is autonomously and automatically adjusted based on the amount of thrust generated by the thrust-controlled variable-pitch propeller 200. To enable automatic adjustment of the pitch of the blades 275, the blades 275 are coupled to the blade hub 250 via the blade holders 270. The blade hub 250 is coupled to or integrated with the ball spline bearing 240, which is slidable along the ball spline shaft 230. The control arm 260 is coupled to the blade hub 250, and when the blade hub 250 slides along the ball spline shaft 230, it causes the blades 275 to rotate and change their pitch position. The thrust spring 220 is disposed around the ball spline shaft 230, and controls the sliding of the ball spline bearing 240 and the blade hub 250 along the ball spline shaft 230 based on the amount of thrust provided by the thrust-controlled variable-pitch propeller 200, thereby autonomously and automatically adjusting the pitch position of the blades 275 based on the amount of thrust. Each component of the thrust-controlled variable-pitch propeller 200 is described in greater detail below.

[0019] In some embodiments, the thrust-controlled variable-pitch propeller 200 includes a top collet 205 coupled near one end of a ball spline shaft 230. In some embodiments, the top collet 205 contacts one end of a thrust spring 220, which is sandwiched between the top collet 205 and a ball spline bearing 240. Generally, the top collet 205 is secured to the ball spline shaft 230 using any suitable fastener (e.g., a set screw), and the components of the thrust spring 220 are secured to the ball spline shaft 230.

[0020] The spinner 210 is an aerodynamic cover for the thrust-controlled variable-pitch propeller 200. Specific embodiments of the spinner 210 are shown in detail in Figure 4. In some embodiments, the spinner 210 is conical as shown. In some embodiments, the spinner 210 is removably coupled to the base mounting plate 280 using another fastener (e.g., a screw). In some embodiments, the spinner 210 includes a plurality of notches 211 that allow the blades 275 to rotate between high-pitch and low-pitch positions as the ball spline bearings 240 slide along the ball spline shaft 230. The length of the notches 211 (e.g., extending upward from the base mounting plate 280 toward the tip of the spinner 210) may be sized according to the length of travel of the ball spline bearings 240 along the ball spline shaft 230 (e.g., determined by the thrust spring 220).

[0021] The thrust spring 220 is any suitable spring disposed around the ball spline shaft 230, and controls the sliding of the ball spline bearing 240 along the ball spline shaft 230 based on the amount of thrust generated by the thrust-controlled variable pitch propeller 200. By controlling the sliding of the ball spline bearing 240 along the ball spline shaft 230, the thrust spring 220 automatically controls the pitch of the blades 275 based on the amount of thrust generated by the thrust-controlled variable pitch propeller 200. In some embodiments, the thrust spring 220 is disposed around the ball spline shaft 230 between the top collet 205 and the ball spline bearing 240. In these embodiments, one end of the thrust spring 220 contacts the top collet 205, and the opposite end of the thrust spring 220 contacts the ball spline bearing 240.

[0022] In some embodiments, the thrust spring 220 is sized to match the desired thrust-to-pitch profile of the aircraft 100. For example, the desired thrust-to-pitch profile may specify the desired pitch of the blades 275 for various thrusts (e.g., in units of lbf) of the motor 290. For example, the following may be the desired pitch of the blades 275 for various thrusts.

[0023] Table 1

[0024] Here, the desired thrust-to-pitch profile specifies a smaller pitch range of 4 to 7 for the vertical flight mode (higher thrust range of 8 to 12.5), and specifies a high pitch of 20 for the horizontal fixed-wing flight mode (lower thrust range of 1 to 3). The size (e.g., compressive strength, length, etc.) of the thrust spring 220 may be selected to compress (e.g., compress for the thrust range of 8 to 12.5) to fit this desired thrust-to-pitch profile.

[0025] The ball spline shaft 230 is a shaft of any appropriate length. The ball spline shaft 230 is coupled to a motor 290 directly or via a base mounting plate 280 and is rotated by the motor 290. In some embodiments, the ball spline shaft 230 includes one or more shaft grooves 231 that allow a ball spline bearing 240 to slide along the ball spline shaft 230 while simultaneously rotating around the ball spline shaft 230.

[0026] The ball spline bearing 240 is configured to slide along the ball spline shaft 230. Specific embodiments of the ball spline bearing 240 are shown in Figure 5. In some embodiments, the ball spline bearing 240 includes a shaft portion 241 and a base plate portion 242. In some embodiments, the shaft portion 241 is tubular in shape, and the diameter of the shaft portion 241 is smaller than the diameter of the base plate portion 242. In some embodiments, the height of the shaft portion 241 is greater than the height (e.g., thickness) of the base plate portion 242. In some embodiments, the shaft portion 241 includes one or more ball bearings (not shown) which are aligned with the shaft groove 231 of the ball spline shaft 230, allowing the ball spline bearing 240 to slide along the ball spline shaft 230 while simultaneously rotating around the ball spline shaft 230. In some embodiments, the base plate portion 242 includes one or more apertures, as shown in the figure, that allow the blade hub 250 to be coupled to the ball spline bearing 240 (for example, via fasteners such as screws).

[0027] The blade hub 250 is a component that connects the blades 275 to the thrust-controlled variable-pitch propeller 200. Specific embodiments of the blade hub 250 are shown in Figures 6A and 6B. In some embodiments, the blade hub 250 is a separate component that is coupled to the ball spline bearing 240 using one or more fasteners, such as screws. In other embodiments, the blade hub 250 may be integrated with the ball spline bearing 240 so that the ball spline bearing 240 and the blade hub 250 are manufactured as a single component. In some embodiments, the blade hub 250 is circular in shape and includes a central aperture 251 that allows the blade hub 250 to slide on the shaft portion 241 of the ball spline bearing 240. In these embodiments, the diameter of the central aperture 251 is slightly larger than the diameter of the shaft portion 241 of the ball spline bearing 240.

[0028] In some embodiments, the blade hub 250 is generally cylindrical and includes two or more flat sides 252 depending on the number of blades 275. For example, if the thrust-controlled variable-pitch propeller 200 includes two blades 275 as shown, the blade hub 250 includes two flat sides 252. The blade hub 250 may also include a center point 253 concentric with the ball spline shaft 230 and two axes (a first axis 254 and a second axis 255 perpendicular to the first axis 254) extending through the center point 253. The flat sides 252 are parallel to each other as shown. Furthermore, each flat side 252 is parallel to the first axis 254 and perpendicular to the second axis 255. Each control arm 260 is coupled to its respective flat side 252 at an eccentric position from the second axis 255 as shown. For example, each upper control arm linkage 261 of the control arm 260 may be coupled to each flat side 252 using fasteners 263 that are screwed into each flat side 252 in a position not aligned with the second axis 255, as shown in the figure. More specifically, each axis 256 of each fastener 263 is not aligned with the second axis 255, nor is it aligned with the axis 256 of the fastener 263 coupled to the opposite flat side 252.

[0029] Each thrust-controlled variable-pitch propeller 200 includes a control arm 260 configured to control the pitch of the blades 275 as the blade hub 250 slides along the ball spline shaft 230. In some embodiments, each control arm 260 includes an upper control arm linkage 261 and a lower control arm linkage 262. The upper control arm linkage 261 is rotatably coupled to the flat side 252 of the blade hub 250 at a position on the flat side 252 of the blade hub 250 that is not aligned with the second axis 255 as described above (e.g., using a fastener 263). The lower control arm linkage 262 is rotatably coupled to both the upper control arm linkage 261 and the base mounting plate 280 as shown. The blade holder 270 is fixedly coupled to the upper control arm linkage 261 (i.e., not rotatably coupled to the upper control arm linkage 261), so that as the blade hub 250 slides along the ball spline shaft 230, the upper control arm linkage 261 rotates, thereby causing the blade holder 270 to rotate. The rotation of the blade holder 270 causes the blade 275 to rotate, thereby changing the pitch of the blade 275.

[0030] The blade 275 is any suitable propeller blade of any appropriate length and shape. The blade 275 can be made from any suitable material such as plastic or metal. Each blade 275 is coupled to the blade holder 270 and configured to rotate between a high-pitch position and a low-pitch position as the ball spline bearing 240 and / or blade hub 250 slide along the ball spline shaft 230.

[0031] The base mounting plate 280 is a component that couples the thrust-controlled variable-pitch propeller 200 to the motor 290. Specific embodiments of the base mounting plate 280 are shown in Figure 7. In some embodiments, the base mounting plate 280 is coupled to the ball spline shaft 230 on the opposite side of the ball spline bearing 240 as viewed from the thrust spring 220. In some embodiments, the base mounting plate 280 includes a clamp flange shaft mount 281 configured to couple the base mounting plate 280 to the ball spline shaft 230. In some embodiments, the base mounting plate 280 includes an outer ring portion 282 configured to couple to the spinner 210 (e.g., using one or more fasteners). In some embodiments, the base mounting plate 280 includes a central portion 283 containing the clamp flange shaft mount 281. The central portion 283 may be coupled to the outer ring portion 282 using a member 284 such that the base mounting plate 280 includes a plurality of apertures 285. The aperture 285 allows the lower control arm linkage 262 of the control arm 260 to connect to the central portion 283 along the side 286 of the central portion 283.

[0032] During operation, the pitch of the blades 275 of the thrust-controlled variable-pitch propeller 200 is autonomously and automatically adjusted (e.g., via the motor 290) based on the amount of thrust generated by the thrust-controlled variable-pitch propeller 200. For example, in horizontal flight (e.g., fixed-wing cruising flight) where the thrust of the thrust-controlled variable-pitch propeller 200 is lower, the blades 275 of the thrust-controlled variable-pitch propeller 200 are automatically adjusted to have a larger blade pitch. In vertical / hovering flight where the thrust of the thrust-controlled variable-pitch propeller 200 is higher, the blades 275 of the thrust-controlled variable-pitch propeller 200 are automatically adjusted to have a smaller pitch. Instead of using heavy and complex mechanisms (e.g., actuators and computer controllers) to adjust the pitch of the blades 275 of a thrust-controlled variable-pitch propeller 200, the thrust-controlled variable-pitch propeller 200 utilizes only mechanical mechanisms to autonomously and automatically control the pitch of the blades 275 based on the amount of thrust generated by the thrust-controlled variable-pitch propeller 200. In particular, the thrust-controlled variable-pitch propeller 200 utilizes a blade hub 250 that can slide along a ball spline shaft 230. A control arm 260 is coupled to the blade hub 250 and restricts the movement of the blade hub 250, causing the blades 275 to rotate and change their pitch position as the blade hub 250 slides along the ball spline shaft 230. The thrust spring 220 is positioned around the ball spline shaft 230 and controls the sliding of the blade hub 250 along the ball spline shaft 230 based on the amount of thrust generated by the thrust-controlled variable-pitch propeller 200, thereby autonomously and automatically adjusting the pitch position of the blades 275 based on the amount of thrust.

[0033] Figures 3A and 3B show different positions of the thrust-controlled variable-pitch propeller 200 during horizontal and vertical flight. In the “horizontal flight” position shown in Figure 3A, the thrust spring 220 is fully extended, pressing the blade hub 250 along the ball spline shaft 230 toward the base mounting plate 280, thereby positioning the blades 275 at their maximum blade pitch 310A (e.g., 12.467 degrees). The thrust spring 220 is uncompressed because a lower amount of thrust is generated by the thrust-controlled variable-pitch propeller 200. In the “vertical flight” position shown in Figure 3B, the thrust spring 220 is fully compressed, allowing the blade hub 250 to slide upward along the ball spline shaft 230 toward the mounting plate 280, thereby positioning the blades 275 at their minimum blade pitch (e.g., 7.413 degrees). The thrust spring 220 is compressed because a higher amount of thrust is generated by the thrust-controlled variable-pitch propeller 200.

[0034] Figure 8 shows a thrust-controlled variable-pitch propeller 800 that, according to a particular embodiment, can be used as a thrust-controlled variable-pitch propeller 130 on the aircraft 100 of Figure 1. Similar to the thrust-controlled variable-pitch propeller 200, some embodiments of the thrust-controlled variable-pitch propeller 800 include a top collet 205, a thrust spring 220, a ball spline shaft 230, a ball spline bearing 240, a blade hub 250, a control arm 260, a blade holder 270, and a base mounting plate 280. Each blade holder 270 is coupled to a blade 275. The base mounting plate 280 couples the thrust-controlled variable-pitch propeller 200 to a motor 290. However, unlike the thrust-controlled variable-pitch propeller 200, the hub 250 of the thrust-controlled variable-pitch propeller 800 includes two halves 810A and 810B fastened together around a ball spline bearing 240 using one or more fasteners 820. Furthermore, each upper control arm linkage 261 of the thrust-controlled variable-pitch propeller 800 is rotatably coupled to a shaft 811A or 811B of the halves 810A or 810B. In some embodiments, the shafts 811A and 811B are each perpendicular to the ball spline shaft 230 and are aligned with each other across the ball spline shaft 230 as shown. The shafts 811A and 811B can be detachably coupled to the halves 810A and 810B (e.g., via screws or fasteners) or permanently coupled to the halves 810A and 810B (e.g., via a single structure, welding, etc.). Furthermore, the upper control arm linkage 261 and lower control arm linkage 262 of the thrust-controlled variable-pitch propeller 800 are modified from those of the thrust-controlled variable-pitch propeller 200. For example, the arms of the upper control arm linkage 261 of the thrust-controlled variable-pitch propeller 800 are rotated by approximately 90 degrees from those of the thrust-controlled variable-pitch propeller 200. In addition, the lower control arm linkage 262 of the thrust-controlled variable-pitch propeller 800 is a linear member, unlike the lower control arm linkage 262 of the thrust-controlled variable-pitch propeller 200.

[0035] While the present disclosure and its merits have been described in detail, it should be understood that various changes, substitutions, and modifications are possible without departing from the spirit and scope of the present disclosure as defined by the appended claims. Furthermore, the scope of this application is not intended to be limited to specific embodiments of the processes, machines, products, material compositions, means, methods, and steps described herein. As will be readily apparent to those skilled in the art from the content of this disclosure, existing or future-developed processes, machines, products, material compositions, means, methods, or steps that perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein can be utilized in accordance with this disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, products, material compositions, means, methods, or steps.

[0036] Furthermore, nothing in this patent document should be construed as suggesting that any particular element, step, or function may be an essential or important element that must be included within the scope of the claims. Also, unless the exact phrases “means for” or “step for” are explicitly used in a particular claim, followed by a participial phrase specifying a function, no claim is intended to invoke Section 112(f) of the U.S. Patent Act, nor any appended claim or claim element. The use of terms such as (but not limited to) “member,” “module,” “apparatus,” “unit,” “component,” “element,” “mechanism,” “device,” “machine,” “system,” “processor,” “processing device,” or “control device” within a claim is intended to refer to a structure well known to those skilled in the art, which may be further modified or enhanced by the features of the claim itself, and is not intended to invoke Section 112(f) of the U.S. Patent Act. Even under the broadest reasonable interpretation in light of this paragraph of the Specification, no claim is intended to invoke Section 112(f) of the U.S. Patent Act unless the specific language described above is present.

[0037] While the accompanying drawings illustrate specific embodiments having certain components, this disclosure also envisions other embodiments having some or all of the components described, as well as additional components not described. The components of this disclosure may be any suitable shape and any suitable configuration.

[0038] As used in this document, "each" refers to each member of a set or each member of a subset of a set. Furthermore, as used in this document, "or" is not necessarily exclusive and, unless explicitly stated, can be inclusive in certain embodiments and may be interpreted as meaning "and / or". Similarly, as used in this document, "and" is not necessarily inclusive and, unless explicitly stated, can be inclusive in certain embodiments and may be interpreted as meaning "and / or".

[0039] This disclosure may be embodied in other specific forms without departing from its spirit or essential features. For example, each of the novel structures described herein may be modified to adapt to specific regional differences or requirements, while maintaining the basic configuration and the structural relationships between them, or while performing the same or similar functions described herein. Accordingly, these embodiments should be construed as illustrative and not restrictive in all respects. Accordingly, the scope of this disclosure may be established by the appended claims rather than by the foregoing description. Accordingly, all modifications that fall within the meaning and equivalent scope of the claims are intended to be encompassed therein. Furthermore, the individual elements of the claims are not well-known, conventional, or prior to them. Instead, the claims are directed to unconventional inventive concepts described in the specification.

[0040] The scope of this disclosure includes any changes, substitutions, modifications, alterations, and modifications to the exemplary embodiments described or shown herein, as can be understood by those skilled in the art. The scope of this disclosure is not limited to the exemplary embodiments described or shown herein. Furthermore, although each embodiment described and shown herein includes a particular component, element, function, operation, or step, any of these embodiments may include, to the extent understandable to those skilled in the art, any combination or permutation of any component, element, function, operation, or step described or shown anywhere herein. Furthermore, any reference in the appended claims to a device or system or component of a device or system adapted, positioned, capable of performing, configured, activated, operable, or operating to perform a particular function includes such device, system, or component, to the extent that such device, system, or component is adapted, positioned, capable, configured, activated, operable, or operating, regardless of whether it or its particular function is activated, turned on, or unlocked.

Claims

1. Fixed wings, Motor and, A variable-pitch propeller coupled to the motor, Main shaft, A hub configured to slide along the main shaft, A plurality of propeller blades, each propeller blade being coupled to a hub and configured to rotate between a high-pitch position and a low-pitch position as the hub slides along the main shaft, and A thrust spring installed around the main shaft, configured to control the sliding of the hub along the main shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust. A variable pitch propeller equipped with An aircraft equipped with [a specific feature / equipment].

2. The aircraft according to claim 1, wherein the aircraft is a vertical take-off and landing (VTOL) aircraft.

3. The aircraft according to claim 1, wherein the motor and the variable-pitch propeller are configured to rotate between a vertical flight position and a horizontal flight position.

4. The aircraft according to claim 1, wherein the pitch position of the propeller blades is automatically adjusted by the thrust spring in the absence of other actuators and computer controllers.

5. The main shaft is a ball spline shaft, The variable-pitch propeller further comprises a ball spline bearing slidably coupled to the ball spline shaft, The hub is coupled to the ball spline bearing. The aircraft according to claim 1.

6. Each propeller blade is connected to the hub via a control arm, and each control arm is An upper control arm linkage rotatably coupled to the hub, The aircraft according to claim 1, further comprising the upper control arm linkage and a lower control arm linkage rotatably coupled to a base mounting plate.

7. The aforementioned hub, A first half comprising a first shaft perpendicular to the main shaft, It comprises a second half having a second shaft perpendicular to the main shaft, The first shaft and the second shaft are aligned with each other across the main shaft. The aircraft according to claim 1.

8. It is a variable-pitch propeller, Ball spline shaft and A collet coupled near one end of the ball spline shaft, A ball spline bearing configured to slide along the ball spline shaft, A thrust spring is installed around the ball spline shaft between the collet and the ball spline bearing, A base mounting plate connected to the ball spline bearing on the opposite side of the ball spline bearing as viewed from the thrust spring, The hub coupled to the ball spline bearing, A plurality of control arms, each control arm being coupled to the hub and the base mounting plate, A plurality of blade holders, each blade holder being coupled to one of the control arms, A plurality of propeller blades, each propeller blade being coupled to one of the blade holders, and configured to rotate between a high-pitch position and a low-pitch position as the ball spline bearing slides along the ball spline shaft, The thrust spring is configured to control the sliding of the ball spline bearing along the ball spline shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust. Variable pitch propeller.

9. Each control arm, An upper control arm linkage rotatably coupled to the hub, The upper control arm linkage and the lower control arm linkage are rotatably coupled to the base mounting plate. A variable pitch propeller according to claim 8, comprising the following:

10. The variable pitch propeller according to claim 8, further comprising a spinner coupled to the base mounting plate, the spinner having a plurality of notches that allow the propeller blades to rotate between the high-pitch position and the low-pitch position as the ball spline bearing slides along the ball spline shaft.

11. The aforementioned hub, The central aperture includes the ball spline shaft and its concentric center point, A first axis extending through the aforementioned center point, A second axis extending through the aforementioned center point and perpendicular to the first axis, It comprises two flat sides, each parallel to the first axis and perpendicular to the second axis, Each control arm is coupled to one of the flat sides at an eccentric position from the second axis. A variable pitch propeller according to claim 8.

12. The variable pitch propeller according to claim 8, wherein the base mounting plate comprises a clamp flange shaft mount configured to connect the base mounting plate to the ball spline shaft.

13. It is a variable-pitch propeller, Ball spline shaft and A ball spline bearing configured to slide along the ball spline shaft, A thrust spring installed around the ball spline shaft, A hub coupled to or integrated with the aforementioned ball spline bearing, Each of the control arms is connected to the hub, Each of the blade holders is connected to one of the control arms, A plurality of propeller blades, each propeller blade being coupled to one of the blade holders, and configured to rotate between a high-pitch position and a low-pitch position as the ball spline bearing slides along the ball spline shaft, The thrust spring is configured to control the sliding of the ball spline bearing along the ball spline shaft based on the amount of thrust provided by the variable-pitch propeller, thereby automatically adjusting the pitch position of the propeller blades based on the amount of thrust. Variable pitch propeller.

14. The variable pitch propeller according to claim 13, further comprising a base mounting plate coupled to the ball spline bearing on the opposite side of the ball spline bearing as viewed from the thrust spring.

15. Each control arm, An upper control arm linkage rotatably coupled to the hub, The upper control arm linkage and the lower control arm linkage are rotatably coupled to the base mounting plate. A variable pitch propeller according to claim 14, comprising the following:

16. The variable pitch propeller according to claim 14, further comprising a spinner coupled to the base mounting plate, the spinner having a plurality of notches that allow the propeller blades to rotate between the high-pitch position and the low-pitch position as the ball spline bearing slides along the ball spline shaft.

17. The variable pitch propeller according to claim 14, wherein the base mounting plate comprises a clamp flange shaft mount configured to connect the base mounting plate to the ball spline shaft.

18. The aforementioned hub, The central aperture includes the ball spline shaft and its concentric center point, A first axis extending through the aforementioned center point, A second axis extending through the aforementioned center point and perpendicular to the first axis, It comprises two flat sides, each parallel to the first axis and perpendicular to the second axis, Each control arm is coupled to one of the flat sides at an eccentric position from the second axis. A variable pitch propeller according to claim 13.

19. The variable pitch propeller according to claim 13, further comprising a collet coupled to the ball spline shaft.

20. The variable pitch propeller according to claim 19, wherein the thrust spring is installed around the ball spline shaft between the collet and the ball spline bearing.

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