Outer rotor motor and aerial drive system having the same

Abstract

The application provides an outer rotor motor and an aviation driving system with the same. The outer rotor motor comprises a stator body and a sleeve. The stator body is provided with an oil inlet and an oil outlet, and has a plurality of stator slots extending along a first direction. Winding is arranged in the stator slots, and the windings in the same stator slot form an axial cooling channel. The sleeve is located outside the stator body. The oil inlet is communicated with the first end of the axial cooling channel along the first direction, and the oil outlet is communicated with the second end of the axial cooling channel along the first direction. The application solves the technical problems of low cooling efficiency and poor sealing of the cooling system of the outer rotor motor in the prior art.

Description

Technical Field

[0001] This invention relates to the field of electric motor technology, and more specifically, to an external rotor motor and an aircraft drive system having the same. Background Technology

[0002] Aviation drive systems refer to drive systems used in the aviation field. They typically consist of an external rotor motor and a reducer, and are suitable for various high-power, high-speed UAV applications. Traditional drive systems mainly use water cooling to cool the motor, thereby achieving efficient heat dissipation. However, water cooling is highly dependent on coolant; coolant leaks or corrosion can severely affect cooling efficiency, thus impacting the operational efficiency and reliability of the drive system.

[0003] In the prior art, such as patent US20190006914A1 ELECTRIC DRIVE UNTI COOLING SYSTEMSAND METHODS, the stator copper wire is mainly cooled by spraying at both ends, with the spraying point being the outer diameter of the copper wire.

[0004] It has the following disadvantages:

[0005] 1) The copper wire is cooled by spraying, but the contact area between the oil and the copper wire is limited, resulting in poor cooling effect;

[0006] 2) The heat transfer path for cooling copper wires in the tank is: copper wire → iron core → oil. Compared with copper wire → oil, there is an additional layer of thermal resistance generated by the iron core, resulting in poor cooling effect.

[0007] 3) The cooling part is mainly in the outer diameter section. The inner diameter copper wire has poor cooling effect and needs to be combined with the rotor to sling oil in order to reduce the temperature of the inner copper wire.

[0008] The patent US2022 / 0200383A1 ELECTRIC MOTOR FOR AIRCRAFT PROPULSION has a complex overall oil circuit and sealing system, and there is also a risk of insulation abnormality.

[0009] Currently, external rotor motors mainly use air-cooling and water-cooling solutions, while oil-cooling solutions lack effective sealing solutions.

[0010] There is currently no effective solution to the above problems. Summary of the Invention

[0011] The main objective of this invention is to provide an external rotor motor and an aviation drive system having the same, so as to solve the technical problems of low cooling efficiency and poor sealing of the cooling system in the prior art.

[0012] To achieve the above objectives, according to one aspect of the present invention, an external rotor motor is provided, comprising: a stator body having an oil inlet and an oil outlet, the stator body having a plurality of stator slots extending along a first direction, slot windings being wound in the stator slots, and an axial cooling channel being formed between two slot windings located in the same stator slot; and a sleeve located outside the stator body; wherein the oil inlet is connected to a first end of the axial cooling channel, and the oil outlet is connected to a second end of the axial cooling channel.

[0013] Furthermore, the end of the axial cooling channel away from the output shaft of the external rotor motor along the first direction forms the first end of the axial cooling channel, and the end of the axial cooling channel close to the output shaft of the external rotor motor along the first direction forms the second end of the axial cooling channel.

[0014] Furthermore, the end of the slot winding furthest from the output shaft along the first direction is the first winding end, and the end of the slot winding closest to the output shaft along the first direction is the second winding end. A first end cooling loop is formed between the first winding end, the stator body, and the sleeve, and a second end cooling loop is formed between the second winding end, the stator body, and the sleeve. The first end cooling loop is connected to the first end and the oil inlet of the axial cooling channel, and the second end cooling loop is connected to the second end and the oil outlet of the axial cooling channel.

[0015] Furthermore, the oil inlet and outlet are symmetrically arranged about the central axis of the external rotor motor along the first projection direction.

[0016] Furthermore, the first direction is the axial direction of the stator body.

[0017] Furthermore, there are multiple oil inlets, which are spaced apart along the circumference of the stator body. There are also multiple oil outlets, which are spaced apart along the circumference of the stator body. The oil inlets and outlets are arranged in pairs, and each oil inlet and its corresponding oil outlet are symmetrical about the central axis of the external rotor motor.

[0018] Furthermore, at least one of the first region where the sleeve is opposite to the end of the first winding and the second region where the sleeve is opposite to the end of the second winding is a multi-layer structure. The multi-layer structure includes a carbon fiber bearing layer and a first glass fiber insulation layer located inside the carbon fiber bearing layer. The first glass fiber insulation layer is also provided with a second glass fiber insulation layer away from the carbon fiber bearing layer.

[0019] Furthermore, the sleeve located between the first region and the second region includes a double-layer structure, which includes a carbon fiber load-bearing layer and a first glass fiber insulation layer located inside the carbon fiber load-bearing layer.

[0020] Furthermore, the sleeve and the stator body adopt a transition fit or an interference fit.

[0021] According to another aspect of the present invention, an aircraft drive system is provided, including an external rotor motor, wherein the external rotor motor is any of the external rotor motors described above.

[0022] By applying the technical solution of this invention, multiple stator slots are built into the stator body, forming axial cooling channels between the windings within the slots. These channels are connected at both ends to oil inlets and outlets for the introduction and export of coolant. The coolant is directly introduced into the axial cooling channels between the windings, achieving direct contact between the coolant and the windings, significantly increasing the heat exchange area and thus improving cooling efficiency. An external sleeve further ensures system sealing and prevents coolant leakage. This solution significantly improves cooling efficiency, simplifies the cooling path, enhances the reliability and safety of the motor, reduces system complexity and the risk of coolant leakage, and provides strong support for motor performance optimization. This application solves the technical problems of low cooling efficiency and poor sealing of the cooling system in existing external rotor motors during operation. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A schematic diagram of the structure of a first embodiment of an external rotor motor according to the present invention is shown;

[0025] Figure 2 A schematic diagram of a second embodiment of an external rotor motor according to the present invention is shown;

[0026] Figure 3 A schematic diagram of an embodiment of the sleeve according to the present invention is shown;

[0027] Figure 4 A schematic diagram of the structure of an embodiment of the second region of the sleeve according to the present invention is shown;

[0028] Figure 5 A structural schematic diagram of an embodiment of the portion between the first and second regions of the sleeve according to the present invention is shown;

[0029] Figure 6 A schematic diagram of the structure of an embodiment of the first region of the sleeve according to the present invention is shown.

[0030] Figure 7 A schematic diagram of a third embodiment of an external rotor motor according to the present invention is shown;

[0031] Figure 8 A schematic diagram of a fourth embodiment of an external rotor motor according to the present invention is shown.

[0032] The above figures include the following reference numerals:

[0033] 101. Stator body; 102. Sleeve; 103. Sealing ring;

[0034] 104. Sealing bonding surface; 105. Oil inlet;

[0035] 106. First end cooling loop; 107. First winding end;

[0036] 108. Axial cooling channel; 109. In-slot winding;

[0037] 110. Second end cooling loop; 111. Second winding end; 112. Oil outlet;

[0038] 200. Carbon fiber load-bearing layer; 201. First fiberglass insulation layer; 202. Second fiberglass insulation layer;

[0039] 203. Upper flange; 204. Lower flange;

[0040] 001. Bolt; 002. Rivet. Detailed Implementation

[0041] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0045] Combination Figures 1 to 8 As shown, according to a specific embodiment of this application, an external rotor motor and an aviation drive system having the same are provided.

[0046] Specifically, the external rotor motor includes a stator body 101 and a sleeve 102. The stator body 101 is provided with an oil inlet 105 and an oil outlet 112. The stator body 101 has a plurality of stator slots extending along a first direction. In-slot windings 109 are wound in the stator slots. An axial cooling channel 108 is formed between two in-slot windings 109 located in the same stator slot. The sleeve 102 is located on the outside of the stator body 101. The oil inlet 105 is connected to the first end of the axial cooling channel 108, and the oil outlet 112 is connected to the second end of the axial cooling channel 108.

[0047] By applying the technical solution of this invention, multiple stator slots are built into the stator body 101, and axial cooling channels 108 are formed between the windings 109 in the slots. The two ends of these channels are connected to oil inlets 105 and oil outlets 112, respectively, for the introduction and export of coolant. The coolant is directly introduced into the axial cooling channels 108 between the windings, achieving direct contact between the coolant and the windings, greatly increasing the heat exchange area and thus improving cooling efficiency. The outer sleeve 102 further ensures system sealing and prevents coolant leakage. This solution significantly improves cooling efficiency, simplifies the cooling path, enhances the reliability and safety of the motor, reduces system complexity and the risk of coolant leakage, and provides strong support for motor performance optimization. This application solves the technical problems of low cooling efficiency and poor sealing of the cooling system in existing external rotor motors during operation.

[0048] Specifically, the end of the axial cooling channel 108 away from the output shaft of the external rotor motor along the first direction forms the first end of the axial cooling channel 108, and the end of the axial cooling channel 108 close to the output shaft of the external rotor motor along the first direction forms the second end of the axial cooling channel 108.

[0049] Optionally, the axial cooling channel 108 is located between the in-slot windings 109 within the same stator slot and extends along a first direction. The first end of the channel, the end furthest from the motor output shaft, communicates with the oil inlet 105 on the stator body 101; the second end of the channel, the end closest to the motor output shaft, communicates with the oil outlet 112 on the stator body 101. This design ensures that coolant can enter from one end of the motor, flow through the channel between the windings, cool the in-slot windings 109, and then exit from the other end of the motor, forming a complete cooling cycle.

[0050] Specifically, the output shaft end of an external rotor motor is typically the area where the in-slot windings 109 are densely packed and current flows most frequently, making it the most concentrated heat source. Designating the second end of the axial cooling channel 108 (closest to the output shaft end) as the coolant outlet means that the coolant, after flowing through the entire winding area, exits from the location of the most concentrated heat source, ensuring that the coolant flow path covers all critical heat-generating areas. The coolant enters the motor from the first end, furthest from the output shaft end, gradually flows through the densely wound area, and finally exits from the second end, where the heat source is most concentrated. This flow path design allows the coolant to absorb heat evenly as it flows through the motor, preventing overheating upon entry and ensuring uniform and efficient heat exchange throughout the cooling process.

[0051] It should be further explained that the axial cooling channel 108 can be configured as corrugated. This shape can increase the contact area between the cooling medium and the winding, improve the heat exchange efficiency, and at the same time, the corrugated structure can also help guide the flow of the cooling medium, reduce flow resistance, and accelerate heat dissipation.

[0052] Furthermore, such as Figure 2As shown, the end of the slot winding 109 furthest from the output shaft along the first direction is the first winding end 107, and the end of the slot winding 109 near the output shaft along the first direction is the second winding end 111. A first end cooling loop 106 is formed between the first winding end 107, the stator body 101, and the sleeve 102. A second end cooling loop 110 is formed between the second winding end 111, the stator body 101, and the sleeve 102. The first end cooling loop 106 is connected to the first end of the axial cooling channel 108 and the oil inlet 105. The second end cooling loop 110 is connected to the second end of the axial cooling channel 108 and the oil outlet 112. This design ensures that the coolant flows from the end of the external rotor motor furthest from the output shaft, first cooling the first winding end 107, then cooling the densely wound area through the axial cooling channel 108, and finally cooling the second winding end 111 near the output shaft. This ensures that the coolant flow path covers the entire heat-generating area of ​​the external rotor motor, improving cooling efficiency and thermal management performance. Simultaneously, this interconnected design also considers coolant flow resistance and venting, optimizing the cooling cycle and reducing the impact of localized residual air on heat dissipation, further improving the efficiency and reliability of the cooling system.

[0053] Specifically, the stator body 101 is the main structural component of the external rotor motor, surrounding and supporting the slot windings 109. In the formation of the first end cooling loop 106, a specific portion of the stator body 101 (typically near the end) together with the first winding end 107 and the sleeve 102 forms a closed annular space. Coolant enters the external rotor motor through the oil inlet 105 on the stator body 101 and then flows into the annular space formed between the first winding end 107 and the stator body 101, i.e., the first end cooling loop 106. The sealing of the first end cooling loop 106 is achieved through the tight fit between the sleeve 102 and the stator body 101.

[0054] Specifically, the second winding end 111 is located at the end of the external rotor motor near the output shaft. A specific part of the stator body 101, together with the second winding end 111 and the sleeve 102, forms a closed annular space, namely the second end cooling loop 110. Coolant flows out from the second end (the end near the output shaft) of the axial cooling channel 108 and directly enters the second end cooling loop 110, flowing through the second winding end 111 and carrying away heat. The fit between the sleeve 102 and the stator body 101, through radial sealing and end face sealing, forms a sealed structure for the second end cooling loop 110, ensuring efficient coolant flow and system reliability, and preventing coolant leakage under high pressure.

[0055] Specifically, the oil inlet 105 is located at the end of the external rotor motor furthest from the output shaft, serving as the entry point for the coolant. After entering through the oil inlet 105, the coolant directly enters the first end cooling loop 106, formed by the first winding end 107 of the slot windings 109, the stator body 101, and the sleeve 102. The first end cooling loop 106 surrounds the first winding end 107, allowing the coolant to directly contact and cool the first winding end 107, thereby removing the heat generated during the initial operation of the external rotor motor. After passing through the first end cooling loop 106, the coolant continues along the axial direction of the external rotor motor through the axial cooling channels 108. The number of axial cooling channels 108 is the same as the number of slot windings 109, ensuring uniform distribution of the coolant, close contact with the windings, and improved heat exchange efficiency. The first end of the axial cooling channel 108 is connected to the first end cooling loop 106, while the second end of the axial cooling channel 108 is connected to the second end cooling loop 110, thus forming an axial flow path for the coolant. This ensures that the coolant can flow from one end of the external rotor motor to the other, effectively cooling the main heat-generating components inside the external rotor motor. After the coolant flows through the axial cooling channel 108 and absorbs heat, it enters the second end cooling loop 110, which is formed between the second winding end 111 of the slot winding 109, the stator body 101, and the sleeve 102. The second end cooling loop 110 surrounds the second winding end 111, allowing the coolant to continue to contact and cool the second winding end 111. Finally, the coolant is discharged from the external rotor motor through the oil outlet 112 and returned to the cooling system for recycling.

[0056] Specifically, such as Figure 1 As shown, the oil inlet 105 and oil outlet 112 are symmetrically arranged 180 degrees about the central axis of the external rotor motor, projected along the first direction. This symmetrical design ensures uniform distribution of coolant inside the motor, avoids local overheating, and improves the motor's operational stability and reliability.

[0057] The symmetrical arrangement of the oil inlet 105 and outlet 112 helps to balance the pressure distribution of the coolant inside the motor, preventing fluid bias to one side and uneven cooling caused by a single inlet / outlet. After entering the motor, the coolant is evenly distributed along the axial direction and then flows out evenly on the other side. This symmetrical arrangement ensures uniform coolant flow in both the axial and radial directions of the motor, achieving comprehensive cooling of the windings and other heat sources. The symmetrical arrangement of the oil inlet 105 and outlet 112 also helps to reduce radial imbalance forces in the motor, preventing the coolant flow from affecting the motor's dynamic balance, thereby improving the motor's stability and operating performance.

[0058] Specifically, the first direction is the axial direction of the stator body 101. Defining the first direction as the axial direction of the stator body 101 is based on the actual distribution of heat sources inside the motor, as well as the optimization requirements for coolant flow path and efficiency. This arrangement ensures that the coolant can contact all heat-generating parts of the motor along the most direct path, improving the cooling effect, while avoiding localized hot spots and reducing coolant flow resistance, which is crucial for improving the motor's thermal management performance.

[0059] Specifically, there are multiple oil inlets 105, which are spaced apart along the circumference of the stator body 101. There are also multiple oil outlets 112, which are spaced apart along the circumference of the stator body 101. The oil inlets 105 and oil outlets 112 are arranged in pairs, and each oil inlet 105 and its corresponding oil outlet 112 are symmetrically arranged about 180 degrees about the central axis of the external rotor motor.

[0060] Specifically, by evenly distributing the oil inlet 105 and oil outlet 112 in the circumferential direction, the fluid dynamics characteristics inside the motor can be optimized, preventing coolant from accumulating or generating eddies at a certain location, which would reduce the cooling effect. The evenly distributed inlet and outlet design allows the coolant to flow more smoothly and evenly inside the motor, improving the flow efficiency and heat exchange performance of the coolant.

[0061] Optionally, during motor operation, components such as the slot winding 109 and the iron core generate heat evenly. However, if there is only one oil inlet 105 and one oil outlet 112, the distribution of coolant inside the motor may be uneven, resulting in poor cooling in certain areas. By increasing the number of oil inlets 105 and 112 and distributing them circumferentially, coolant can enter and exit the motor evenly from multiple locations, thereby improving the distribution of coolant inside the motor and enhancing the uniformity of the cooling effect.

[0062] Specifically, the added oil inlet 105 and oil outlet 112 allow the coolant to cover the heat-generating areas of the motor more quickly and directly, reducing the path length of the coolant from the oil inlet 105 to the slot winding 109 and from the slot winding 109 to the oil outlet 112, thereby improving heat exchange efficiency. Furthermore, the design of multiple oil inlets and outlets increases the coolant flow rate, further accelerating heat dissipation and thus improving the overall efficiency of the cooling system.

[0063] Optionally, the design of multiple oil inlets 105 and outlets 112 also provides a certain degree of system redundancy. Even if one inlet or outlet fails, the remaining inlets or outlets can still ensure the normal flow of coolant, maintain the cooling effect of the motor, and improve the reliability of the cooling system and the operational stability of the motor.

[0064] Furthermore, such as Figures 3 to 6 As shown, at least one of the first region of the sleeve 102 opposite to the first winding end 107 and the second region of the sleeve 102 opposite to the second winding end 111 is a multi-layer structure. The multi-layer structure includes a carbon fiber load-bearing layer 200 and a first glass fiber insulation layer 201 located inside the carbon fiber load-bearing layer 200. A second glass fiber insulation layer 202 is also provided on the first glass fiber insulation layer 201 away from the carbon fiber load-bearing layer 200.

[0065] Specifically, the multi-layer structure, from the inside out, includes a second glass fiber insulation layer 202, a first glass fiber insulation layer 201, and a carbon fiber load-bearing layer 200. The insulation performance of the motor is crucial for its normal operation and safety. Since the windings are in direct contact with the coolant, the innermost layer should prioritize insulating materials to prevent direct electrical contact between the coolant (especially conductive liquids) and the windings, thus avoiding short circuits. The second glass fiber insulation layer 202 and the first glass fiber insulation layer 201 possess excellent insulation properties, effectively isolating the windings from the coolant and ensuring the motor's electrical safety. The second glass fiber insulation layer 202 and the first glass fiber insulation layer 201 are made of low-weight woven glass fiber fabric with a thickness of 0.1 mm. Their close fit reduces the impact of weave gaps on insulation. The carbon fiber load-bearing layer 200 is located on the outer side of the multi-layer structure, fully utilizing the high strength, high stiffness, and low weight characteristics of carbon fiber material. This design effectively resists the high pressure generated under oil cooling conditions, while reducing deformation caused by vibration and mechanical stress during motor operation, ensuring the stability and long-term reliability of the entire sleeve structure. Placing the carbon fiber load-bearing layer 200 on the outer layer also facilitates inspection of its sealing and structural integrity during maintenance. If wear or damage is found in the carbon fiber layer, it can be relatively easily replaced or repaired without affecting the integrity of the inner insulation material and the motor's insulation performance.

[0066] Optionally, during motor operation, there is a risk of leakage between the slot winding 109 and the carbon fiber support layer 200, especially in the contact areas between the first winding end 107, the second winding end 111, and the sealing sleeve 102, i.e., the first and second regions, which are locations with a higher risk of leakage. This region is covered with a second glass fiber insulation layer 202 and a first glass fiber insulation layer 201. This covering significantly increases the insulation thickness and strength between the end windings and the carbon fiber support layer, enhancing the sealing effect and structural rigidity, and reducing coolant leakage. After covering, a curing process is required to ensure the structural stability and insulation performance of the material. The curing process can employ autoclave, RTM (resin transfer molding), or compression molding methods, depending on the size, shape, and manufacturing conditions of the motor.

[0067] Specifically, the sleeve 102 located between the first region and the second region includes a double-layer structure, which includes a carbon fiber load-bearing layer 200 and a first glass fiber insulation layer 201 located inside the carbon fiber load-bearing layer 200.

[0068] The winding end area, being in direct contact with the coolant and possessing a high voltage potential, is a region with a high risk of leakage in the motor. Therefore, a second glass fiber insulation layer 202 is added to form a thicker and more robust insulation layer, ensuring that no electrical short circuit occurs between the motor winding and the carbon fiber support layer under high-pressure oil cooling conditions. In the non-winding end area, the sleeve 102 employs a double-layer structure: a carbon fiber support layer 200 and a first glass fiber insulation layer 201. The insulation risk is lower in the non-winding end area, hence the double-layer structure, retaining only the necessary first glass fiber insulation layer 201 to maintain good mechanical properties while reducing unnecessary weight increase and achieving a lightweight design.

[0069] Multi-layer insulation structures may affect heat conduction efficiency because glass fiber is less thermally conductive than carbon fiber. In the winding end region, sacrificing some heat conduction efficiency is necessary due to its insulation requirements. However, in the non-winding end region, retaining only the double-layer structure of the carbon fiber load-bearing layer 200 and the first glass fiber insulation layer 201 ensures better heat conduction, thereby improving cooling efficiency.

[0070] The introduction of multi-layer structures increases manufacturing costs and process complexity. Using a double-layer structure in areas with lower insulation requirements can simplify the manufacturing process, reduce costs, and simultaneously ensure the overall performance and reliability of the motor.

[0071] Specifically, the sleeve 102 and the stator body 101 adopt a transition fit or an interference fit. The transition fit or interference fit can ensure that a tight physical connection is formed between the sleeve 102 and the stator body 101, thereby reducing coolant leakage. Especially under high-pressure oil cooling conditions, this tight fit helps to improve sealing performance, prevent coolant from leaking into the non-cooled areas of the motor, and ensure the efficient operation of the cooling system.

[0072] The use of a transition or interference fit increases the friction between the sleeve 102 and the stator body 101, thereby improving the mechanical connection strength between them. This design helps to resist the vibration generated during motor operation and the centrifugal force generated under high-speed rotation, maintains a stable connection between the sleeve and the stator body, and reduces positional displacement or structural loosening caused by mechanical movement.

[0073] It should be further explained that the stator body 101, sleeve 102, sealing ring 103, and sealing bonding surface 104 constitute the cooling cavity. The sleeve 102 and stator body 101 are fitted with either a transition fit or an interference fit. The sleeve 102 is tightly fitted to the stator body 101 through at least one of radial sealing and end-face sealing. The radial seal is formed by the sealing ring 103 and the sealing bonding surface 104 in the radial direction (perpendicular to the axis) between the sleeve and the stator body, preventing radial leakage of coolant. The end-face seal is formed between the end face of the sleeve and the end face of the stator body, preventing axial leakage of coolant. The combination of radial sealing and end-face sealing creates multiple sealing barriers, significantly improving the sealing performance of the entire system and reducing the risk of coolant leakage in different directions.

[0074] A radial seal is employed, with a sealing ring 103 installed at the joint between the stator body 101 and the sleeve 102. The sealing ring 103 is typically made of an elastic material, such as rubber or silicone, which, through its elastic deformation, adheres tightly to the contact surfaces of the stator body 101 and the sleeve 102 under high pressure, forming an effective sealing barrier. The sealing bonding surface 104, the contact surface between the stator body 101 and the sleeve 102, is specially treated to enhance the sealing effect. The sealing bonding surface 104 can be coated with sealant or other adhesive materials to ensure a tight fit between the stator body 101 and the sleeve 102, preventing coolant leakage from these joints under high pressure.

[0075] Specifically, the sleeve 102 is preferably made of glass fiber and carbon fiber composite material, with a wall thickness preferably of 0.8–1 mm. Further, to reduce the deformation of the sleeve 102 under hydraulic pressure, carbon fiber is preferably used as the main material, with a predominantly circumferential layup. This better adapts to the annular structure of the cooling sleeve, enhancing its circumferential strength while maintaining good sealing performance. The sleeve 102 is formed through processes such as autoclave molding, RTM (resin transfer molding), or compression molding, ensuring a good interface seal between the sleeve 102 and the stator body 101, greatly reducing the risk of leakage.

[0076] It should be further noted that composite material molding can be achieved through various processes, including 3D weaving, woven fabric laying or unidirectional tape laying, and chopped fiber laying. The choice of these processes depends on the specific design of the motor. In some cases, metal or plastic can also be used as substitutes for composite materials.

[0077] It should be further noted that the external rotor motor also includes a flange, which consists of an upper flange 203 and a lower flange 204.

[0078] like Figure 7As shown, bolt 001 passes through a pre-drilled hole (or threaded hole) on the upper flange 203 and engages with a corresponding threaded hole or nut on the stator body 101 to securely connect the upper flange 203 to the stator body 101. Bolted connections provide high mechanical strength and are suitable for applications requiring the resistance to large axial forces, such as resisting the axial impact of hydraulic pressure and vibrations during motor operation.

[0079] Rivet 002 is used to connect and fix the lower flange 204 to the cooling sleeve 102 to enhance structural rigidity and sealing, and prevent coolant leakage. Rivet connection is usually quick and easy.

[0080] To improve the overall flange fixing rigidity and achieve effective weight reduction, it is preferable to use composite material integral molding, such as... Figure 8 The upper flange 203 and lower flange 204 shown can be made of composite material + plastic + composite material sandwich flange, which can effectively reduce costs.

[0081] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0082] 1. Through the immersion cooling design, compared with the traditional spray cooling, the coolant directly contacts the winding in the slot, which greatly improves the heat exchange efficiency. At the same time, the arrangement of the axial cooling channel 108 ensures the uniformity of cooling of the winding in the slot, effectively controls the temperature rise of the winding in the motor slot, and improves the operating efficiency and reliability of the motor.

[0083] 2. The composite material molded sleeve combined with the radial and end face sealing scheme, as well as the sealing ring and sealing bonding surface, forms a multi-layer sealing structure, which greatly reduces the possibility of coolant leakage, simplifies the sealing components, reduces the failure rate caused by sealing problems, and ensures the long-term stable operation of the oil cooling system.

[0084] 3. The use of glass fiber and carbon fiber composite materials as the main material of the sealing sleeve not only provides the necessary oil pressure resistance and reduces deformation, but also effectively improves the inner diameter insulation effect of the motor stator oil cooling system, reduces the risk of leakage, and achieves overall structural lightweighting, thus reducing costs.

[0085] The above embodiments can also be used in the field of aviation drive equipment technology. That is, according to another aspect of the present invention, an aviation drive system is provided, including an external rotor motor, wherein the external rotor motor is any of the external rotor motors in the above embodiments.

[0086] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0087] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0088] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An external rotor motor, characterized in that, include: The stator body (101) is provided with an oil inlet (105) and an oil outlet (112). The stator body (101) has a plurality of stator slots extending along a first direction. In-slot windings (109) are wound in the stator slots. An axial cooling channel (108) is formed between two in-slot windings (109) located in the same stator slot. A sleeve (102) is located on the outside of the stator body (101); The oil inlet (105) is connected to the first end of the axial cooling channel (108), and the oil outlet (112) is connected to the second end of the axial cooling channel (108). The end of the slot winding (109) away from the output shaft along the first direction is the first winding end (107), and the end of the slot winding (109) near the output shaft along the first direction is the second winding end (111). A first end cooling loop (106) is formed between the first winding end (107), the stator body (101), and the sleeve (102), and a second end cooling loop (110) is formed between the second winding end (111), the stator body (101), and the sleeve (102). At least one of the first region of the sleeve (102) opposite to the first winding end (107) and the second region of the sleeve (102) opposite to the second winding end (111) is a multi-layer structure, and the portion of the sleeve (102) located between the first region and the second region includes a double-layer structure, wherein the inner side of the first region, the second region and the portion between the first region and the second region of the sleeve (102) is made of insulating material.

2. The external rotor motor according to claim 1, characterized in that, The axial cooling channel (108) forms a first end at the end away from the output shaft of the external rotor motor along the first direction, and forms a second end at the end close to the output shaft of the external rotor motor along the first direction.

3. The external rotor motor according to claim 2, characterized in that, The first end cooling loop (106) is connected to the first end of the axial cooling channel (108) and the oil inlet (105), and the second end cooling loop (110) is connected to the second end of the axial cooling channel (108) and the oil outlet (112).

4. The external rotor motor according to claim 1, characterized in that, The oil inlet (105) and the oil outlet (112) are symmetrically arranged about 180 degrees about the central axis of the external rotor motor when projected along the first direction.

5. The external rotor motor according to any one of claims 1 to 4, characterized in that, The first direction is the axial direction of the stator body (101).

6. The external rotor motor according to claim 1, characterized in that, There are multiple oil inlets (105), which are spaced apart along the circumferential direction of the stator body (101). There are multiple oil outlets (112), which are spaced apart along the circumferential direction of the stator body (101). The oil inlets (105) and the oil outlets (112) are arranged in pairs. Each oil inlet (105) and the corresponding oil outlet (112) are symmetrically arranged about 180 degrees about the central axis of the external rotor motor.

7. The external rotor motor according to claim 3, characterized in that, The multi-layer structure includes a carbon fiber load-bearing layer (200) and a first glass fiber insulation layer (201) located inside the carbon fiber load-bearing layer (200). The first glass fiber insulation layer (201) is further provided with a second glass fiber insulation layer (202) away from the carbon fiber load-bearing layer (200).

8. The external rotor motor according to claim 7, characterized in that, The double-layer structure includes the carbon fiber load-bearing layer (200) and a first glass fiber insulation layer (201) located inside the carbon fiber load-bearing layer (200).

9. The external rotor motor according to claim 1, characterized in that, The sleeve (102) and the stator body (101) adopt a transition fit or an interference fit.

10. An aircraft drive system, comprising an external rotor motor, characterized in that, The external rotor motor is the external rotor motor according to any one of claims 1 to 9.

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