Annular shaftless motor integrated with duct

Abstract

The invention discloses an annular shaftless motor integrated with a duct, is used for solving the technical problems of center pneumatic blockage, complex structure, large dead weight and the like of a traditional duct propulsion system, and belongs to the technical field of aviation propulsion. The motor comprises a stator assembly on the static side and a rotor assembly on the rotating side, the rotor assembly comprises a duct, the duct is of an annular structure, a rotor and fan blades are fixed in the duct, the fan blades are located on the side, away from the stator assembly, of the duct, the stator assembly comprises a base, a flow guide plate is rigidly connected to the base, and the flow guide plate is located on the side, away from the stator assembly, of the duct. An annular stator is installed on the upper side of the base, the annular stator is coaxially installed on the base, and the rotor assembly and the stator assembly are provided with rotation constraints.

Description

Technical Field

[0001] This invention belongs to the field of aviation propulsion technology, and specifically relates to a ring-shaped shaftless motor integrated with a duct. Background Technology

[0002] The propulsion system of an aircraft, especially for new aviation platforms such as multi-rotor unmanned aerial vehicles and electric vertical takeoff and landing (eVTOL) aircraft, directly determines the aircraft's endurance, payload efficiency, and acoustic stealth characteristics through the comprehensive performance of its power unit. In the current field of aviation propulsion, ducted fan systems are widely used in various small and medium-sized aircraft due to their higher thrust efficiency, better noise shielding, and higher operational safety compared to isolated propellers.

[0003] However, most mainstream ducted propulsion systems currently use the traditional "center-shaft driven" configuration. This means the motor, as an independent power unit, is placed at the geometric center of the duct flow field, driving the fan blades through a central shaft and mechanical hub. This layout has inherent physical drawbacks: firstly, the motor body, cooling structure, and support ribs located at the center of the flow field significantly obstruct the high-speed intake airflow, creating a significant "center blockage effect," leading to intake distortion and reduced aerodynamic efficiency; secondly, a mechanical safety clearance must be maintained between the blade tip of the rotating blade and the stationary inner wall of the duct, which can cause severe airflow leakage under high pressure differentials, resulting in "tip vortex" losses and severely limiting further improvements in propeller efficiency.

[0004] To overcome the limitations of center-driven propulsion, some explorations of "rim-driven" or "shaftless propulsion" technologies, which move the motor's stator and rotor to the periphery, have emerged in the industry. However, these technologies still face significant challenges in practical engineering applications. Most existing conventional rim-driven motors directly adopt the design concepts of traditional industrial motors, using heavy silicon steel cores as the stator frame. This results in a sharp increase in stator weight under large-diameter rim-driven conditions, severely reducing the power-to-weight ratio of aerospace propulsion systems. Furthermore, due to the cogging effect of the core, existing solutions often involve significant torque ripple and electromagnetic noise, making it difficult to meet the stringent requirements of aircraft for smooth control and quiet flight.

[0005] In summary, current technologies lack a comprehensive solution that can simultaneously address issues such as pneumatic center blockage, mechanical transmission dead weight, and low integration of large-diameter drive systems. Traditional shaftless motors with iron cores struggle to achieve a balance between lightweight design and high efficiency, and the support and heat dissipation structures for the stator and rotor are often complex and cumbersome. Summary of the Invention

[0006] The purpose of this invention is to provide a ring-shaped shaftless motor integrated with the duct to solve the technical problems of traditional ducted propulsion systems, such as central aerodynamic blockage, complex structure, and large dead weight.

[0007] This invention is achieved using the following technical solution:

[0008] An integrated ring-shaped shaftless motor includes a stator assembly on the stationary side and a rotor assembly on the rotating side. The rotor assembly includes a duct, which is an annular structure. A rotor and a fan blade are fixed inside the duct. The fan blade is located on the side of the duct away from the stator assembly. The stator assembly includes a base, on which a guide plate is rigidly connected. An annular stator is mounted on the upper side of the base and is coaxially mounted on the base. The rotor assembly and the stator assembly are provided with rotational constraints.

[0009] The duct serves as the supporting frame for the entire rotor, with the fan blade tips fixed to its inner wall. The rotor, i.e., the permanent magnet, is located on the inner wall of the duct near the stator assembly. In this invention, the duct, fan blades, and rotor form a single unit. The duct guides airflow and also functions as the motor housing, thus achieving a completely shaftless drive. The stator assembly achieves a high degree of integration between structural support and electromagnetic drive. The base and guide plate can be integrally molded, providing both mechanical support and airflow rectification for the shaftless motor. A ring-shaped stator replaces the iron-core stator found in traditional drive motors.

[0010] During operation, the stationary stator assembly forms a stable support frame through a base and rigidly connected guide plates, fixing the annular stator to the base. This serves as both an electromagnetic drive source and an auxiliary function for airflow rectification and heat dissipation. The rotating side abandons the traditional central shaft hub, directly utilizing the duct as the rotor skeleton, thus forming an integrated rotating body of "duct-blade-permanent magnet". In terms of structural fit, the annular stator and the permanent magnets on the inner wall of the rotor are directly coupled. The magnetic field generated after energization directly drives the rotation of the outer duct assembly. A rotational constraint interface is established between the two, ensuring that the rotor assembly can smoothly levitate or roll relative to the stator assembly when there is no central shaft.

[0011] More preferably, the annular stator is a ring-shaped distributed coil, which directly couples with the rotor permanent magnet to drive the rotor through the magnetic field generated by the ring-shaped distributed coil. By replacing the traditional iron core stator with a ring-shaped distributed coil, this invention utilizes the flattened and lightweight characteristics of the coil, along with a guide plate, to reduce the weight of the stator system and improve heat dissipation efficiency while ensuring high torque output.

[0012] More preferably, the rotor assembly and stator assembly achieve rotational constraint by mechanical rolling or magnetic levitation.

[0013] Mechanical rolling is achieved by installing rolling elements between the contact surfaces of the stator and rotor assemblies, such as ceramic balls, steel balls, or needle rollers. This method converts the rotor's rotational motion into circumferential rolling friction, thus replacing the traditional central bearing support and ensuring that the rotor assembly can roll smoothly relative to the stator.

[0014] The magnetic levitation scheme employs a non-contact connection method, utilizing magnetic force to levitate the rotor above the stator for rotation. This method aims to create a flexible rotary connection interface between the stator and rotor, allowing the rotor assembly to rotate smoothly without mechanical contact through magnetic support.

[0015] The core of this invention lies in its innovative motor structure, which has the advantages of greatly reducing system weight and reducing costs through structural reuse. This invention is particularly suitable for propulsion systems of aircraft such as UAVs and eVTOL. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] In the diagram: 1-fan blade, 2-duct, 3-permanent magnet, 4-ring stator, 5-base. Detailed Implementation

[0020] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0021] In this description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Example 1

[0025] An integrated ring-shaped shaftless motor includes a stator assembly on the stationary side and a rotor assembly on the rotating side. The rotor assembly includes a duct, which is an annular structure. A rotor and a fan blade are fixed inside the duct. The fan blade is located on the side of the duct away from the stator assembly. The stator assembly includes a base, on which a guide plate is rigidly connected. An annular stator is mounted on the upper side of the base and is coaxially mounted on the base. The rotor assembly and the stator assembly are provided with rotational constraints. In a specific implementation, the fan blade can be manufactured as an integral part of the duct.

[0026] The annular stator is a ring-shaped distributed coil. This design utilizes the flattened and lightweight characteristics of the coil, combined with the structural path of the guide plate, to significantly reduce the dead weight of the stator system and improve heat dissipation efficiency while ensuring high torque output.

[0027] The fan blades are directly fixed to the duct guard ring, and a permanent magnet assembly is provided on the inner circumferential side of the duct guard ring.

[0028] The rotor assembly and stator assembly achieve rotational constraint through mechanical rolling or magnetic levitation.

[0029] The working principle is as follows:

[0030] This invention relates to an integrated rotor assembly that deeply integrates fan blades, ducts, and the rotor. Structurally, the rotor assembly is a ring without a central shaft or hub, allowing airflow to pass through completely unimpeded. The duct serves as the primary support frame for the entire rotor, and the fan blades are directly fixed to the inner wall of the duct through integral molding or high-strength connections, forming a rigid whole. Simultaneously, permanent magnets are rigidly mounted on the circumference of the duct's inner wall. This design directly utilizes the rotation of the outer duct to drive the inner fan blades, completely eliminating the obstruction of airflow by the motor's central shaft structure and significantly improving intake efficiency.

[0031] The stator assembly of this invention consists of a base, guide plates, and an annular stator. The base secures the entire shaftless motor to the aircraft fuselage, and the guide plates are positioned between the base and the annular stator. These guide plates not only provide structural support but also regulate the airflow into the duct and utilize airflow cooling to aid in motor heat dissipation. The annular stator employs a ring-shaped, plate-like distributed coil rigidly mounted on the guide plates, replacing the traditional iron core stator. When the ring-shaped, plate-like distributed coil is energized, the generated magnetic field directly acts on the permanent magnets on the rotor, driving the entire rotor assembly to operate efficiently, reducing weight while ensuring high torque output.

[0032] The duct (rotor side) and the base (stator side) are not rigidly fixed, but a rotational constraint interface is established through mechanical rolling or magnetic levitation to achieve smooth rotor rotation on the stator. In other words, to ensure smooth rotation of the rotor assembly on the stator assembly, a flexible rotational constraint interface is constructed between the stator and rotor. Depending on the application requirements, the rotational constraint of the rotor relative to the stator can be achieved mechanically, by installing rolling components such as ceramic balls, steel balls, or needle rollers between the stator and rotor contact surfaces to allow the rotor to roll smoothly; or it can be achieved non-contact magnetic levitation, using magnetic force to levitate the rotor and allow it to rotate on the stator.

[0033] This invention, through its innovative topology, aims to achieve a high degree of structural reuse between the motor and the duct, significantly reducing system weight; through its electromagnetic and transmission characteristics, it perfectly matches the high torque and low speed operating requirements of the ducted fan, enabling it to continuously operate at its high efficiency point.

[0034] This invention eliminates the traditional central shaft, bearings, and independent motor housing, transforming the rotor's rotational motion into circumferential rolling friction, thus replacing the traditional central bearing support.

[0035] This invention proposes a deeply integrated annular rim drive topology configuration.

[0036] This invention eliminates the central shaft and hub of a traditional motor, achieving complete hollowing of the flow field. While significantly reducing system weight, it can meet the stringent requirements of aircraft for low-speed, high-torque, and high aerodynamic efficiency.

[0037] This invention is a novel propulsion device that deeply integrates the drive components with the ducted aerodynamic structure, eliminates the heavy iron core, and has efficient heat dissipation capabilities, aiming to achieve substantial technological breakthroughs in weight reduction, efficiency improvement, and system reliability enhancement.

[0038] This invention abandons the central shaft and hub of traditional motors and adopts a hollow ring topology configuration, in which the stator assembly achieves a high degree of integration between structural support and electromagnetic drive.

[0039] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Although detailed descriptions have been provided with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments, and they should all be covered within the protection scope of the claims.

Claims

1. A ring-shaped shaftless motor integrated with a duct, characterized in that: The device includes a stationary stator assembly and a rotating rotor assembly. The rotor assembly includes a duct, which is an annular structure. A rotor and a fan blade are fixed inside the duct. The fan blade is located on the side of the duct away from the stator assembly. The stator assembly includes a base, on which a guide plate is rigidly connected. An annular stator is mounted on the upper side of the base and is coaxially mounted on the base. The rotor assembly and the stator assembly are provided with rotational constraints.

2. The ring-shaped shaftless motor integrated with the duct as described in claim 1, characterized in that: The annular stator is a ring-shaped distributed coil.

3. The ring-shaped shaftless motor integrated with the duct as described in claim 2, characterized in that: The rotor assembly and stator assembly achieve rotational constraint through mechanical rolling or magnetic levitation.

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