Oil-cooled composite rotor and motor

Abstract

The application relates to the technical field of motor equipment, and discloses an oil-cooled composite material rotor and a motor. The oil-cooled composite material rotor comprises a composite material rotating shaft, a cooling sheath and magnetic steel. An inner cavity of the composite material rotating shaft is used for passing in cooling oil, and an oil throwing hole is arranged on the shaft wall of the axial middle part. The cooling sheath is arranged outside the composite material rotating shaft and is provided with an annular groove and a plurality of axial oil through holes. The annular groove is communicated with the oil throwing hole, the axial oil through holes are arranged on the axial two sides of the annular groove and are communicated with the annular groove, and the magnetic steel is attached to the outer periphery of the cooling sheath. When the composite material rotating shaft rotates, the cooling oil in the inner cavity is thrown into the annular groove through the oil throwing hole and is distributed to the axial oil through holes on the axial two sides, so as to flow from the axial middle part of the rotor to both ends and directly cool the magnetic steel, thereby shortening the cooling path, balancing the axial temperature difference of the rotor, reducing the heat transfer thermal resistance, simultaneously realizing the lightweight and high-strength characteristics of the rotor by using the composite material rotating shaft, and improving the power density of the motor.

Description

Technical Field

[0001] This application relates to the field of electrical equipment technology, and in particular to an oil-cooled composite material rotor and motor. Background Technology

[0002] With the development of aviation electrification, technologies such as eddy electric hybrid and electric propulsion have placed higher demands on the speed, power density and weight of aircraft generators. High speed, high strength, efficient heat dissipation and lightweight have become the core objectives of aircraft motor rotor design. Existing high-speed motor rotors mostly adopt a structure of steel shaft and silicon steel sheet core with embedded magnets, and cooling oil channels are opened on the silicon steel sheets to cool the rotor. However, in the current rotor structure, on the one hand, the steel shaft and silicon steel sheet core are heavy, the thermal conductivity of silicon steel sheets is low, and the thermal resistance between the magnets and the cooling oil is high, which restricts the improvement of rotor heat dissipation efficiency, critical speed and power density. On the other hand, the cooling oil mostly flows from one end of the rotor to the other end and flows out through radial holes. The cooling oil flows through the entire rotor in a one-way way, and the temperature continues to rise after absorbing heat, resulting in a large temperature difference between the two ends of the rotor axis. Some rotor structures use slotted baffles in the middle of the rotor to split the cooling oil from the middle to both ends. Although this structure can balance the axial temperature difference of the rotor, the baffles increase the axial ineffective length of the rotor, resulting in a complex rotor structure and difficult assembly. In addition, the current cooling oil channels are all opened on the silicon steel sheet core, which is only suitable for embedded magnet rotors, not for surface-mounted magnet rotors.

[0003] Therefore, how to achieve both lightweight and high strength rotors while efficiently and uniformly cooling surface-mounted magnets is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an oil-cooled composite material rotor that achieves both rotor lightweighting and high strength while providing efficient and uniform cooling of surface-mounted magnets.

[0005] Another objective of this application is to provide an electric motor comprising the aforementioned oil-cooled composite material rotor.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] An oil-cooled composite material rotor, comprising:

[0008] A composite material shaft, wherein the composite material shaft is a hollow shaft and the inner cavity is used to pass through cooling oil, and an oil-throwing hole extending radially is provided on the shaft wall at the axial center of the composite material shaft;

[0009] A cooling sleeve is provided on the outside of the composite material shaft. The cooling sleeve has an annular groove and a plurality of axial oil passage holes arranged circumferentially along the cooling sleeve. The annular groove is corresponding to and communicates with the oil slinger hole. The plurality of axial oil passage holes are distributed on both sides of the annular groove and communicate with the annular groove respectively.

[0010] The magnet is attached to the outer periphery of the cooling sleeve. When the composite material shaft rotates, the cooling oil in the inner cavity is thrown into the annular groove through the oil throwing hole and then diverted to the axial oil passages on both sides of the annular groove to cool the magnet.

[0011] Preferably, in the above-mentioned oil-cooled composite material rotor, there are multiple oil-throwing holes, and the multiple oil-throwing holes are evenly spaced along the circumference of the composite material rotor shaft.

[0012] Preferably, in the above-mentioned oil-cooled composite material rotor, a plurality of axial oil passages are evenly and densely distributed along the circumference of the cooling sleeve, and the axial oil passages are microchannel structures.

[0013] Preferably, in the above-mentioned oil-cooled composite material rotor, the composite material shaft is formed by winding carbon fiber, and the winding direction of the carbon fiber is 0° / ±β° / 90°, wherein the value of β is in the range of 30°-60°.

[0014] Preferably, the oil-cooled composite material rotor further includes a wound sheath, which is made of carbon fiber wound or pressed onto the outer periphery of the magnet.

[0015] Preferably, in the above-mentioned oil-cooled composite material rotor, the cooling sleeve is an aluminum-based silicon carbide sleeve; the coefficient of linear expansion of the cooling sleeve is between the coefficient of linear expansion of the composite material shaft and the coefficient of linear expansion of the magnet.

[0016] Preferably, in the above-mentioned oil-cooled composite material rotor, an insulating layer is provided on the outer peripheral surface of the cooling sleeve, and the insulating layer is a micro-arc oxidation layer or a ceramic coating.

[0017] Preferably, in the above-mentioned oil-cooled composite material rotor, the cooling sleeve is interference-fitted with the composite material shaft, and the cooling sleeve is fitted onto the outside of the composite material shaft by heat fitting or press fitting.

[0018] Preferably, in the above-mentioned oil-cooled composite material rotor, there are multiple magnets, and the multiple magnets are arranged in segments along the axial direction of the cooling sleeve, and the magnets in adjacent segments are arranged with opposite poles.

[0019] An electric motor comprising an oil-cooled composite rotor as described in any of the preceding claims.

[0020] As can be seen from the above technical solution, this application provides an oil-cooled composite material rotor, which mainly includes a composite material shaft, a cooling sleeve, and magnets. The composite material shaft adopts a hollow shaft structure, with its inner cavity for introducing cooling oil. Simultaneously, a radial oil-throwing hole is opened on the shaft wall at the axial center of the composite material shaft. When the rotor rotates, the cooling oil is radially thrown out through the oil-throwing hole under centrifugal force, achieving reliable delivery of the cooling oil without the need for an additional oil pump. Furthermore, the oil-throwing hole in the middle allows the cooling oil to be diverted from the middle position of the composite material shaft axially to both ends, structurally avoiding the problem of excessive temperature difference at both ends of the axial direction caused by the cooling oil flowing through the entire rotor in a single pass. It also eliminates the need for structures such as oil passage baffles, shortening the axial length of the rotor and simplifying the assembly structure. Based on this, the cooling sleeve is fitted onto the composite material... On the outer side of the rotating shaft, the cooling sleeve has an annular groove that corresponds to and communicates with the oil slinger hole. The cooling sleeve also has multiple axial oil passages, arranged circumferentially along the cooling sleeve and distributed on both sides of the annular groove. Cooling oil thrown out through the oil slinger hole enters the annular groove and, under pressure, is evenly distributed to each axial oil passage, allowing the cooling oil to flow along the entire axial length of the magnet. Furthermore, the magnet is attached to the outer circumference of the cooling sleeve, with only the wall thickness of the cooling sleeve separating the magnet from the cooling oil. This results in a short heat transfer path and low thermal resistance, allowing the cooling oil to quickly carry away the eddy current heat generated by the magnet and the aerodynamic heat generated by the shaft, achieving direct and uniform cooling of the surface-mounted magnet. Simultaneously, the rotating shaft uses composite materials, utilizing their high specific strength and low density to reduce rotor weight while improving the rotor's critical speed and structural strength. In summary, this application achieves both rotor lightweighting and high strength while providing efficient and uniform cooling of the surface-mounted magnet, thus improving the motor's power density and operational reliability. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the side cross-sectional structure of an oil-cooled composite material rotor provided in an embodiment of this application;

[0023] Figure 2 A side view of an oil-cooled composite material rotor provided in an embodiment of this application;

[0024] Figure 3 This is an exploded view of an oil-cooled composite material rotor provided in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the side cross-sectional structure of a cooling sleeve provided in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the lateral cross-sectional structure of a composite material shaft provided in an embodiment of this application;

[0027] Figure 6 for Figure 5 Side view.

[0028] in:

[0029] 1-Composite material shaft; 11-Oil slinger hole; 2-Magnet; 3-Wound sheath; 4-Cooling sheath; 41-Annular groove; 42-Axial oil passage hole; 43-Outer peripheral wall. Detailed Implementation

[0030] The core of this application is to disclose an oil-cooled composite material rotor, which achieves both lightweight and high strength of the rotor while providing efficient and uniform cooling of the surface-mounted magnets.

[0031] Another core aspect of this application is to provide an electric motor comprising the aforementioned oil-cooled composite material rotor.

[0032] To enable those skilled in the art to better understand the present application, embodiments of the present application will be described below with reference to the accompanying drawings. Furthermore, the embodiments shown below do not limit the scope of the invention as described in the claims. Additionally, the complete contents of the structures represented in the following embodiments are not limited to those necessary for the solution of the invention described in the claims.

[0033] like Figure 1 and Figure 2 As shown, this application embodiment provides an oil-cooled composite material rotor, which mainly includes a composite material shaft 1, a cooling sleeve 4, and a magnet 2. The three are arranged and fixedly connected in a radial direction from the inside to the outside to form an integral rotor structure. The composite material shaft 1 is a hollow shaft structure, and its inner cavity is axially through to form an oil inlet channel for cooling oil. Cooling oil enters the inner cavity from one end of the composite material shaft 1. At the same time, an oil-throwing hole 11 extending radially is opened on the shaft wall at the axial center of the composite material shaft 1. The oil-throwing hole 11 connects the inner cavity of the composite material shaft 1 with the external space.

[0034] It should be noted that the hollow shaft structure serves two purposes: firstly, it acts as a channel for delivering cooling oil, allowing the oil to be delivered directly to the axial center of the rotor; secondly, it significantly reduces the weight of the shaft, thus achieving lightweighting of the rotor's core load-bearing components.

[0035] Based on this structure, such as Figure 3 and Figure 4As shown, the cooling sleeve 4 is fitted onto the outside of the composite material shaft 1 and fixedly connected thereto. The cooling sleeve 4 has an annular groove 41 and multiple axial oil passages 42 arranged circumferentially around it. For example... Figure 4 As shown, the annular groove 41 is opened on the inner wall side of the cooling sleeve 4, and it is radially corresponding to and connected to the oil slinger hole 11. Multiple axial oil passage holes 42 are distributed on both sides of the annular groove 41 and are respectively connected to the annular groove 41. In the radial layer, the cooling sleeve 4 forms a three-layer structure from the inside out, consisting of an annular groove 41, an axial oil passage hole 42, and an outer peripheral wall 43. The annular groove 41 is located in the inner layer and is an annular groove that receives and collects the cooling oil thrown out by the oil throwing hole 11, serving as a confluence and pressure equalization function. The axial oil passage hole 42 is located in the middle layer and serves as an axial oil delivery channel for the cooling oil. The outer peripheral wall 43 is located in the outer layer and is a solid wall surface on the radial outer side of the axial oil passage hole 42. It seals the radial outer side of each axial oil passage hole 42 to prevent the cooling oil from leaking radially during the flow process, ensuring that all the cooling oil thrown into the annular groove 41 flows directionally along the axial oil passage hole 42 to both ends of the cooling sleeve 4. At the same time, the outer surface of the outer peripheral wall 43 forms a complete and continuous cylindrical mating surface.

[0036] Furthermore, such as Figure 1 and Figure 3 As shown, the magnet 2 is attached to the outer peripheral wall 43 of the cooling sleeve 4, forming a surface-mounted magnet structure. The inner surface of the magnet 2 is in contact with the outer surface of the outer peripheral wall 43. The magnet 2 and the cooling oil in the axial oil passage 42 are separated only by the wall thickness of the outer peripheral wall 43, so as to minimize the distance between the magnet 2 and the cooling oil and improve the cooling effect of the cooling oil on the magnet 2.

[0037] In the oil-cooled composite material rotor provided in the embodiments of this application, such as Figure 1As shown, during operation, the composite material shaft 1 drives the cooling sleeve 4 and the magnet 2 to rotate at high speed. Under the action of centrifugal force, the cooling oil in its inner cavity is radially thrown out through the oil throwing hole 11 and enters the annular groove 41. Under the action of oil pressure, it is diverted from the annular groove 41 to the axial oil passages 42 on both sides of the axis, and then flows out along the axis to both ends of the cooling sleeve 4. In the above oil circuit structure, the oil throwing power comes from the centrifugal force of the rotor rotation, and there is no need to set up an additional oil pump for pressurization, resulting in high oil supply reliability. At the same time, the cooling oil is diverted from the middle of the rotor axis to both ends simultaneously. Compared with the single-pass cooling method where the cooling oil flows from one end to the other, the cooling path is shortened by half, the heat absorption temperature rise of the cooling oil is halved, and the temperature difference between the two ends of the rotor axis is significantly reduced. In addition, there is no need to set up the oil passage baffle in the prior art, which shortens the axial ineffective length of the rotor and simplifies the assembly structure. In addition, the magnet 2 is in direct contact with the outer peripheral wall 43. The eddy current heat generated by the interaction between the armature magnetic field and its own magnetic field, and the aerodynamic heat generated by the high-speed rotation of the shaft, are transferred to the cooling oil through the wall thickness of the outer peripheral wall 43. The heat transfer path is short and the thermal resistance is low, which realizes the local and uniform cooling of the surface-mounted magnet 2.

[0038] It should also be noted that the composite material shaft 1 utilizes the high specific strength and low density characteristics of composite materials to reduce rotor weight while improving the rotor's critical speed and structural strength. In summary, the rotor of this embodiment achieves both lightweighting and high strength while simultaneously enabling efficient and uniform cooling of the surface-mounted magnets 2, thereby improving the motor's power density and operational reliability.

[0039] Furthermore, in order to improve the uniformity of coolant flow, such as Figure 2 and Figure 3 As shown, in some embodiments of this application, multiple oil-throwing holes 11 are provided, and the multiple oil-throwing holes 11 are evenly spaced along the circumference of the composite material shaft 1. Each oil-throwing hole 11 is located in the axial middle of the composite material shaft 1 and extends radially. The multiple oil-throwing holes 11 are opened at equal angles on the same circumferential cross section in the axial middle of the composite material shaft 1.

[0040] Correspondingly, the multiple oil-throwing holes 11 evenly distributed in the circumference form a multi-point oil inlet fit with the annular groove 41. When the rotor rotates, the cooling oil in the inner cavity is synchronously thrown out through each oil-throwing hole 11 along the entire circumference on the same axial section. The oil inlet volume at each circumferential position in the annular groove 41 tends to be consistent, and the oil pressure in the annular groove 41 is evenly distributed in the circumference. This avoids the problem of excessively high local oil pressure and insufficient local oil supply in the annular groove 41 caused by oil inlet through a single hole or a small number of holes. In turn, it ensures that the oil inlet volume of each axial oil passage hole 42 distributed on both sides of the annular groove 41 is consistent, so that the cooling intensity of the magnet 2 is uniform in all parts along the circumference, and the problem of dead angles due to uneven circumferential cooling is eliminated.

[0041] It should also be noted that, given a fixed total flow area for oil slinging, setting multiple oil slinging holes 11 can correspondingly reduce the diameter of a single oil slinging hole 11, thereby reducing the degree of damage to the continuity of the composite material shaft 1's shaft wall caused by the opening, reducing stress concentration at the opening, and thus helping to maintain the shaft wall strength of the composite material shaft 1. In addition, the multiple oil slinging holes 11 are symmetrically distributed in the circumferential direction, and the mass of material removed by the opening is balanced in the circumferential direction, which will not lead to mass eccentricity problems. This helps to maintain the dynamic balance of the rotor, avoid additional excitation force and vibration caused by eccentricity during high-speed rotation, and ensure the smooth operation of the rotor.

[0042] It should be further explained that in other feasible embodiments, the oil slinger holes 11 can also be configured as two or more rows arranged in a staggered manner along the axial direction, and each row of oil slinger holes 11 is connected to the annular groove 41 at the corresponding position, so as to disperse the influence of the opening structure on the shaft wall strength while satisfying a larger cooling oil flow.

[0043] Furthermore, in some embodiments of this application, a plurality of axial oil passage holes 42 are evenly and densely distributed along the circumference of the cooling sleeve 4, that is, the circumferential spacing between adjacent axial oil passage holes 42 is small, preferably retaining only the necessary partition wall thickness, so that axial oil passage holes 42 pass through at any circumferential position of the cooling sleeve 4. In some embodiments, such as Figure 2 As shown, 24 axial oil passages 42 are provided on a single circular cross-section. The densely arranged axial oil passages 42 ensure that each part of the magnet 2 has a nearby cooling channel along the circumference. The heat generated at each part of the magnet 2 can be transferred to the cooling oil in the adjacent axial oil passages 42 through a very short radial path, eliminating dead zones of uneven circumferential cooling and ensuring the consistency of the circumferential temperature distribution of the magnet 2. At the same time, the densely arranged small-pitched channels maximize the total flow area of ​​the cooling oil within the limited cross-section of the cooling sleeve 4, and can obtain a larger cooling oil flow rate under the same oil supply pressure, thereby improving the overall heat dissipation capacity.

[0044] Furthermore, the axial oil passage 42 can also adopt a microchannel structure, that is, the axial oil passage 42 is designed as a densely packed channel with a small diameter. According to the principle of convective heat transfer, under the same total flow area, reducing the diameter of a single hole and increasing the number of channels can significantly increase the contact area between the cooling oil and the hole wall, and reduce the hydraulic diameter of the channel, thereby improving the convective heat transfer coefficient between the cooling oil and the cooling jacket 4, and enhancing the heat transfer effect. The densely packed microchannels also make the temperature distribution of the cooling jacket 4 more uniform along the circumference and axial direction, further reducing the circumferential and axial temperature difference of the magnet 2. In addition, the microchannel structure is opened inside the cooling jacket 4, which maintains the integrity and continuity of the outer surface of the outer peripheral wall 43 while achieving strong heat transfer, and does not affect the attachment and fit of the magnet 2.

[0045] It should also be noted that the cross-sectional shape of the axial oil passage 42 can be set to a circle, or it can be set to a rectangle, waist shape, or other shapes.

[0046] Furthermore, in the oil-cooled composite material rotor provided in this application embodiment, the composite material shaft 1 is formed by winding carbon fiber. Specifically, it can be manufactured by wet winding of carbon fiber bundles or by winding and curing carbon fiber cloth. The formed composite material shaft 1 is an integral hollow tubular structure with uniform mass distribution along the axial and circumferential directions, which facilitates ensuring the dynamic balance accuracy of the rotor. It should be further noted that the winding direction of the carbon fiber adopts a layup combination of 0° / ±β° / 90°, with fibers in each direction wound in layers and cured and connected into one piece. The fibers in the 0° direction are arranged along the axial direction of the rotor shaft to mainly bear the bending load during high-speed rotor rotation, providing axial bending stiffness to the shaft and suppressing rotor deflection. The fibers in the ±β° direction are spirally and obliquely intertwined, with the winding directions of the two layers of fibers being symmetrical and opposite relative to the axial direction. They jointly bear the torque transmitted by the shaft and suppress torsional deformation. The value of β ranges from 30° to 60°. In some embodiments, the value of β is 60°. The specific value can be determined by optimizing the rotor dynamics analysis. When the transmitted torque is large, β can be taken as a smaller value to enhance torsional resistance, and when the bending stiffness requirement is high, β can be taken as a larger value. The fibers in the 90° direction are wound circumferentially to mainly bear the centrifugal load generated during high-speed rotor rotation, ensuring the circumferential strength of the shaft and preventing radial expansion deformation of the hollow shaft under centrifugal force.

[0047] Through the above-mentioned multi-angle layup design, the composite material shaft 1 can give full play to the high strength advantage of carbon fiber along the fiber direction in various stress directions such as bending, torsion, and centrifugation. The material is fully utilized, so that the strength and stiffness of the shaft can reach or even exceed the level of steel shaft of the same size. The density of carbon fiber composite material is only 1.55-1.60g / cm³, which is much lower than that of steel, and the weight of the shaft is greatly reduced. The reduction in rotor weight and the maintenance of stiffness together improve the critical speed of the rotor, enabling the rotor to avoid the resonance zone and operate stably at higher speeds, providing structural protection for the high-speed and high-power-density design of the motor.

[0048] Furthermore, such as Figure 1 and Figure 3As shown, the oil-cooled composite material rotor provided in this embodiment also includes a wound sheath 3. The wound sheath 3 is made of carbon fiber wound or pressed onto the outer periphery of the magnet 2 to completely cover and constrain the magnet 2 to the outer peripheral wall 43 of the cooling sheath 4. It should be noted that when the surface-mounted magnet 2 is attached to the outer surface of the cooling sheath 4, the magnet 2 bears a huge centrifugal load when the rotor rotates at high speed. The magnet 2, which is only connected by adhesive, is at risk of loosening. In this embodiment, the wound sheath 3 uses the high strength of carbon fiber in the circumferential direction to form a circumferential sheath around the magnet 2. The clamping constraint counteracts the centrifugal load on the magnet 2, reliably holding the magnet 2 on the outer peripheral wall 43, preventing the magnet 2 from loosening, shifting, or breaking off under centrifugal force, thus improving the safety of the rotor during high-speed operation. At the same time, a certain tension force can be applied to the fiber during the carbon fiber winding process, so that the formed winding sheath 3 forms a pre-compression force on the magnet 2, and the magnet 2 is elastically pressed on the outer peripheral wall 43, further improving the reliability of the magnet 2 under vibration and impact conditions, and reducing the contact thermal resistance between the magnet 2 and the outer peripheral wall 43.

[0049] In addition, compared with the solution of using metal sheath to constrain magnets, the carbon fiber wound or press-fit wound sheath 3 has low density and thinness, which has a minimal increase in rotor weight and will not weaken the lightweight effect of composite material rotor.

[0050] Furthermore, in some embodiments of this application, the cooling sleeve 4 is an aluminum-based silicon carbide sleeve, that is, the cooling sleeve 4 is made of aluminum-based silicon carbide composite material. This material has aluminum alloy as the matrix and silicon carbide particles as the reinforcement, combining the low density and high thermal conductivity of aluminum with the high strength and low expansion characteristics of silicon carbide. It should be noted that, from the perspective of thermal conductivity, the thermal conductivity of aluminum-based silicon carbide can reach 150-190 W / (m·K), which is much higher than that of silicon steel sheets, which is about 20 W / (m·K). According to the thermal resistance formula Rt=h / (λ·A) (where h is the material thickness, λ is the thermal conductivity, and A is the thermal contact area), under the same thickness and thermal contact area, the thermal resistance of the aluminum-based silicon carbide sheath is only about one-tenth of that of the silicon steel sheet structure. The thermal resistance between the magnet 2 and the cooling oil is greatly reduced, and the eddy current heat of the magnet 2 can be quickly conducted through the outer peripheral wall 43 to the cooling oil in the axial oil passage 42. The heat dissipation efficiency is significantly improved, which can reduce the working temperature of the magnet 2 and avoid the risk of high-temperature demagnetization.

[0051] Furthermore, from a lightweighting perspective, aluminum-based silicon carbide has a density of approximately 2.98-3.00 g / cm³, far lower than steel, and its tensile strength can reach 340-420 MPa. Combined with the hollow structure of the internal axial oil passages 42, this ensures the structural strength of the cooling jacket 4 while further achieving rotor lightweighting. From a thermal matching perspective, aluminum-based silicon carbide has a coefficient of linear expansion of 4.0-6.5 × 10⁻⁻⁻⁶. 6 / K, is between carbon fiber composite materials (0-1×10⁻ along the fiber direction) 6 / K) and sintered NdFeB magnets (orientation direction 6.0-6.5×10⁻ 6 During the rotor temperature rise, the thermal expansion of the cooling sleeve 4 is between that of the composite material shaft 1 and the magnet 2, forming a transition buffer between them. This coordinates the thermal deformation differences between the various materials, avoids excessive stress concentration caused by expansion mismatch in the hot state, prevents the magnet 2 from cracking and breaking due to thermal stress, and ensures the structural reliability and connection stability of the rotor under wide temperature range conditions.

[0052] Based on the above embodiments, an insulating layer is also provided on the outer peripheral surface of the cooling sleeve 4. Specifically, the insulating layer can be a micro-arc oxidation layer or a ceramic coating. It should be specifically noted that when micro-arc oxidation is used, the cooling sleeve 4 is placed in an electrolyte and a high voltage is applied, so that a dense ceramic oxide layer is grown in situ on its outer peripheral surface. This oxide layer is metallurgically bonded to the outer peripheral wall 43, with a strong bond and excellent insulation performance. The insulating layer not only isolates the electrical coupling path between the cooling sleeve 4 and the magnet 2, weakens the eddy currents induced by the magnetic field changes of the magnet 2 on the surface of the cooling sleeve 4, and reduces the eddy current heat loss, but also has higher hardness and better wear resistance, so as to form surface protection for the outer peripheral wall 43 of the cooling sleeve 4 and avoid scratches and wear on the surface of the outer peripheral wall 43 during assembly and operation.

[0053] In addition, the conductive aluminum-based silicon carbide cooling sleeve 4 is fitted on the outside of the composite material shaft 1, which can also form an electromagnetic shielding layer on the internal composite material shaft 1, weaken the eddy current induced by the magnetic field penetrating to the composite material shaft 1, reduce shaft current problems, and help protect bearings and other supporting components.

[0054] It should be further noted that in some other embodiments of this application, the insulating layer can also be formed by spraying ceramic coatings such as alumina and zirconium oxide. The spraying process is highly adaptable and the coating thickness is controllable, and the same effect of surface insulation and reduction of eddy current coupling can be achieved.

[0055] Furthermore, in the oil-cooled composite material rotor provided in this application embodiment, the cooling sleeve 4 is interference-fitted with the composite material shaft 1. Specifically, the cooling sleeve 4 is fitted onto the outside of the composite material shaft 1 by heat fitting or press fitting. When heat fitting is used, the cooling sleeve 4 is first heated as a whole, causing its inner hole to expand and its diameter to increase. Then, the cooling sleeve 4 is fitted into the predetermined axial position of the composite material shaft 1. After cooling and shrinking, the cooling sleeve 4 hugs the outer surface of the composite material shaft 1, forming a strong interference connection. There is no axial pressing force during the heat fitting assembly process, resulting in less assembly damage and higher connection quality. When press fitting is used, axial pressure is applied to the end face of the cooling sleeve 4 by a pressure device, pressing the cooling sleeve 4 axially to the predetermined position on the outside of the composite material shaft 1. The press fitting process is simple and has high assembly efficiency.

[0056] The interference fit connection allows the cooling sleeve 4 and the composite material shaft 1 to reliably transmit torque through the friction of their mating surfaces, eliminating the need for additional connecting parts such as keys, pins, and bolts. This avoids the weakening of the shaft wall strength caused by additional connecting parts that would require holes or slots in the composite material shaft 1, and also avoids the impact of added mass on the rotor's dynamic balance. At the same time, the cooling sleeve 4, fitted on the outside of the composite material shaft 1, is equivalent to adding a reinforcing sleeve to the outside of the shaft. The cooling sleeve 4 and the composite material shaft 1 share the bending load, providing the rotor with additional bending strength and improving the overall rigidity of the rotor, which is beneficial for further increasing the rotor's critical speed.

[0057] Furthermore, such as Figure 3 As shown, in the oil-cooled composite material rotor provided in this application embodiment, there are multiple magnets 2. The multiple magnets 2 are arranged in segments along the axial direction of the cooling sleeve 4. Each segment of magnet 2 is arranged circumferentially to form the magnetic pole of that segment, and the magnetic poles of adjacent segments of magnet 2 are staggered, that is, the magnetic poles of two adjacent segments of magnet 2 are staggered by a certain angle in the circumferential direction. Since this application adopts a surface-mount magnet structure, the magnets 2 are directly attached to the outer surface of the outer peripheral wall 43 of the cooling sleeve 4. The segmentation and staggered arrangement of the magnets 2 can be achieved by controlling the circumferential position angle of each segment of magnet 2 during bonding and assembly. Unlike the embedded magnet structure, it does not require designing various types of silicon steel sheets with different lamination forms for different axial segments and stacking them in segments. The magnet structure is simple, easy to form and assemble, and has low manufacturing cost. The segmented pole offset setting of magnet 2 can offset the phase of the cogging torque generated by each segment of magnetic pole, so that the cogging torque of each segment cancels each other out, thereby reducing the overall cogging torque and torque pulsation of the motor, reducing torque fluctuation, vibration and noise during rotor operation, and improving the smoothness and output quality of motor operation. It is particularly advantageous for application scenarios such as aviation motors where vibration and noise requirements are stringent.

[0058] It should also be noted that each segment of the magnet 2 is attached to a section of the cooling sleeve 4 with axial oil passages 42. Each axial oil passage 42 penetrates the corresponding section of the magnet 2 along the axial direction, allowing each magnet 2 to receive local cooling from the cooling oil within the passage. The segmented arrangement of the magnets 2 does not disrupt the continuity of the cooling oil path, ensuring the consistency and reliability of cooling for each magnet 2 segment. It should be noted that since this oil-cooled composite material rotor possesses the technical effects provided by any of the above embodiments, the motor also possesses the technical effects provided by any of the above embodiments, which will not be elaborated upon further here.

[0059] The terms "first," "second," "left side," and "right side," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may not be defined in the listed steps or units, but may include steps or units not listed.

[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An oil-cooled composite material rotor, characterized in that, include: A composite material shaft (1) is a hollow shaft with an inner cavity for passing through cooling oil. A radially extending oil-throwing hole (11) is provided on the shaft wall at the axial center of the composite material shaft (1). Cooling sleeve (4) is sleeved on the outside of the composite material shaft (1). The cooling sleeve (4) has an annular groove (41) and a plurality of axial oil passage holes (42) arranged circumferentially along the cooling sleeve (4). The annular groove (41) is correspondingly provided with the oil slinger hole (11) and communicates with the oil slinger hole (11). The plurality of axial oil passage holes (42) are distributed on both sides of the annular groove (41) and communicate with the annular groove (41) respectively. Magnet (2), the magnet (2) is attached to the outer periphery of the cooling sleeve (4). When the composite material shaft (1) rotates, the cooling oil in the inner cavity is thrown into the annular groove (41) through the oil throwing hole (11) and diverted to each of the axial oil passage holes (42) on both sides of the annular groove (41) to cool the magnet (2).

2. The oil-cooled composite material rotor according to claim 1, characterized in that, There are multiple oil-throwing holes (11), and the multiple oil-throwing holes (11) are evenly spaced along the circumference of the composite material rotating shaft (1).

3. The oil-cooled composite material rotor according to claim 1, characterized in that, Multiple axial oil passages (42) are evenly distributed along the circumference of the cooling sleeve (4), and the axial oil passages (42) are microchannel structures.

4. The oil-cooled composite material rotor according to claim 1, characterized in that, The composite material shaft (1) is formed by winding carbon fiber, and the winding direction of the carbon fiber is 0° / ±β° / 90°, and the value of β is in the range of 30°-60°.

5. The oil-cooled composite material rotor according to claim 1, characterized in that, It also includes a winding sheath (3), which is made of carbon fiber wound or pressed onto the outer periphery of the magnet (2).

6. The oil-cooled composite material rotor according to claim 1, characterized in that, The cooling sleeve (4) is an aluminum-based silicon carbide sleeve; the coefficient of linear expansion of the cooling sleeve (4) is between the coefficient of linear expansion of the composite material shaft (1) and the coefficient of linear expansion of the magnet (2).

7. The oil-cooled composite material rotor according to claim 6, characterized in that, The outer peripheral surface of the cooling sleeve (4) is provided with an insulating layer, which is a micro-arc oxidation layer or a ceramic coating.

8. The oil-cooled composite material rotor according to claim 1, characterized in that, The cooling sleeve (4) is interference-fitted with the composite material shaft (1), and the cooling sleeve (4) is fitted onto the outside of the composite material shaft (1) by heat fitting or press fitting.

9. The oil-cooled composite material rotor according to claim 1, characterized in that, There are multiple magnets (2), and the multiple magnets (2) are arranged in segments along the axial direction of the cooling sleeve (4), and the magnets (2) in adjacent segments are staggered.

10. An electric motor, characterized in that, Includes an oil-cooled composite material rotor as described in any one of claims 1 to 9.

Images