A jacket-cooled rotor structure and electric machine

Abstract

This invention discloses a sheath-cooled rotor structure and motor, belonging to the field of motor rotor cooling technology. It includes: a flow-splitter ring and rotor segments located on both sides of the flow-splitter ring; N uniformly distributed radial flow channels are provided on the flow-splitter ring, where N is an integer greater than 1; the inner port of each radial flow channel is a flow inlet, and the outer port is a flow outlet; each rotor segment includes a rotor core and a permanent magnet; each rotor segment is sheathed, with the sheath consisting of an inner sheath and an outer sheath from the inside out; the inner sheath has N cooling microchannels extending from the flow-splitter ring to the axial end of the rotor; the port of the cooling microchannel located in the middle of the rotor is connected to a flow outlet, and the port located at the axial end of the rotor is the cooling microchannel outlet; the inner sheath is not completely interrupted by the cooling microchannels in the circumferential direction. This invention can effectively improve the cooling efficiency of the rotor while ensuring the protective function of the rotor sheath.

Description

Technical Field

[0001] This invention belongs to the field of motor rotor cooling technology, and more specifically, relates to a sheath-cooled rotor structure and a motor. Background Technology

[0002] In aerospace, electric vehicles, multi-electric / all-electric aircraft, and industrial robots, high-energy-product rare-earth permanent magnet materials are widely used to meet weight power density and volume power density requirements, making high-density permanent magnet motor systems a research hotspot. Rotor thermal management of permanent magnet motors is considered a key limiting factor for improving motor power density. High power density is usually achieved by increasing motor speed, which increases rotor core losses. Simultaneously, the thermal insulation gap at high speeds results in high thermal resistance between the rotor and the cooling medium, making heat dissipation difficult. Therefore, rotor eddy current losses easily lead to excessive rotor temperature rise. Rotor overheating not only causes irreversible demagnetization of the permanent magnets but also causes bearing lubrication system failure. Deformation caused by rotor thermal stress can lead to sheath interference changes or even rotor rubbing, affecting the safe and reliable operation of high-speed permanent magnet motors.

[0003] Permanent magnet motors generate significant centrifugal force during high-speed rotation. For surface-mounted and high-speed internal permanent magnet motors, a protective sleeve must be added to the outside of the rotor to protect the rotor core and permanent magnets. Current technology typically involves adding a high-strength carbon fiber sheath or a high-strength non-magnetic alloy protective sleeve to the rotor core. In high-temperature environments, the carbon fiber sheath softens and is damaged due to the poor heat resistance of the resin used for bonding; in such cases, an alloy sheath is a better choice. However, alloy protection measures generate significant eddy current losses within the protective sleeve, similar to those of the permanent magnets themselves, which poses a significant challenge to the motor's heat dissipation.

[0004] Current rotor cooling typically employs a cooling structure similar to stator water jacket cooling, designing a cooling channel structure. By introducing the cooling medium into the cooling channel, the thermal resistance between the medium and the cold source is reduced, thereby enhancing the rotor's heat dissipation capacity. Air cooling and oil cooling are commonly used methods. For high-power density, high-power motors, the rotor usually requires a more efficient cooling method. High-efficiency rotor cooling technology for high-power density permanent magnet motor systems has become one of the key technologies that urgently needs to be solved for high-power permanent magnet motors.

[0005] Traditional rotor cooling structures are mostly designed on the rotor core, resulting in relatively large cooling channels. Furthermore, the placement of these cooling channels is limited by the influence of the motor's magnetic circuit and power transmission, thus restricting rotor cooling efficiency. Patent document CN217508397U discloses a motor rotor cooling oil circuit structure. This structure introduces cooling oil simultaneously from pressure plates on both sides of the rotor via the shaft. Weight-reducing holes serve as rotor cooling oil channels, directing the oil flow to the opposite pressure plate to cool the end windings. This cooling structure provides a certain cooling effect, and the use of weight-reducing holes minimizes the impact on electromagnetic performance. However, because the weight-reducing holes are far from the magnets, the direct cooling effect on the magnet's eddy currents is poor. For rotors with high losses, further improvement in cooling efficiency is still needed.

[0006] In the patent application publication number CN107749678A, a cooling structure device for a permanent magnet motor rotor sheath is provided. In this device, an axial ventilation channel structure is used between the rotor sheath and the iron core. By appropriately extending the rotor iron core, the magnetic circuit reluctance is reduced, minimizing the increase in magnetic circuit reluctance due to the ventilation channel, while providing better heat dissipation capacity. This structure essentially breaks the circumferential connection of the sheath, making the rotor protection function of the sheath within the thickness of the axial ventilation channel basically ineffective. It is necessary to increase the thickness of the outer side of the sheath to ensure the rotor protection capability, which is equivalent to adding the electromagnetic air gap of the axial ventilation channel thickness out of thin air. Even if the magnetic circuit reluctance is reduced by extending the rotor iron core, it still has a significant impact on the motor output performance.

[0007] In summary, the existing rotor cooling structure needs further improvement in its cooling effect on the rotor. Summary of the Invention

[0008] In view of the shortcomings of the existing technology and the need for improvement, the present invention provides a rotor structure and motor with a sheath cooling system, the purpose of which is to effectively improve the rotor cooling efficiency while ensuring the protective function of the rotor sheath.

[0009] To achieve the above objectives, according to one aspect of the present invention, a jacketed cooling rotor structure is provided, comprising: a flow divider ring and rotor segments located on both sides of the flow divider ring;

[0010] The flow divider ring is provided with N evenly distributed radial flow channels; the inner port of the radial flow channel is the flow inlet, and the outer port is the flow outlet.

[0011] The rotor segment includes a rotor core and a permanent magnet; each rotor segment is fitted with a protective sleeve, which consists of an inner protective sleeve and an outer protective sleeve from the inside out.

[0012] The inner sheath is provided with N cooling microchannels extending from the flow divider ring to the axial end of the rotor; the port of the cooling microchannel in the middle of the rotor is connected to a flow guide outlet, and the port at the axial end of the rotor is the outlet of the cooling microchannel; the inner sheath is not completely interrupted by the cooling microchannel in the circumferential direction.

[0013] Where N is an integer greater than 1.

[0014] In some alternative embodiments, cooling microchannels are disposed on the outer surface of the inner sheath.

[0015] In some alternative embodiments, the cooling microchannels are spiral microchannels.

[0016] Furthermore, the cooling microchannels in the two rotor segments are symmetrically arranged about the flow divider ring, and the rotation direction of the cooling microchannels matches the rotation direction of the rotor.

[0017] In some optional embodiments, the cooling microchannel flow path is a square wave type, sawtooth type, or sinusoidal type microchannel flow path. The cooling microchannel groove type is one or more of the following: arc shape, elliptical arc shape, rectangle, trapezoid, or irregular shape, as well as a microchannel groove type that includes the above groove types with rounded corners.

[0018] In some optional embodiments, the inner sheath includes a flow channel layer and a connecting layer arranged sequentially from the inside to the outside;

[0019] The cooling microchannel includes a first microchannel and a second microchannel disposed in the channel layer, and a set of third microchannels disposed in the connecting layer;

[0020] The first microchannel extends from the shunt ring toward the axial end of the rotor but does not extend to the axial end of the rotor; the second microchannel extends from the axial end of the rotor toward the shunt ring but does not extend to the shunt ring; the third microchannels in the same group are parallel to each other, and the two ends of each third microchannel are connected to the first microchannel and the second microchannel, respectively.

[0021] Furthermore, the sheath-cooled rotor structure provided by the present invention further includes: an isolation and protective layer disposed between the rotor segment and the sheath.

[0022] Furthermore, the third microchannel is set along the circumferential direction or has a preset non-zero angle with the circumferential direction.

[0023] According to another aspect of the present invention, a permanent magnet motor is provided, comprising a rotating shaft, a rotor, a stator, and a housing arranged sequentially from the inside to the outside;

[0024] The rotor is any of the above-described sheath-cooled rotor structures provided by the present invention;

[0025] The rotating shaft is a hollow structure with one end closed and the other end open, and N cooling medium outlets are provided in the middle, which are connected to the N radial guide channels in the rotor.

[0026] Based on the above-mentioned sheath-cooled rotor structure provided by the present invention, during operation, after the cooling medium is introduced through the rotating shaft, the cooling medium will be guided by the central flow ring, so that the cooling medium flows to the cooling microchannel in the inner sheath of the rotor. Through the centrifugal force of the high-speed rotation of the motor rotor and the pressure of the pump used to pump in the cooling medium, the cooling medium covers the entire sheath surface inside the rotor sheath along the microchannel, and finally flows out at both ends of the rotor axis to further cool the stator end windings, and then collects at the bottom of the motor housing, so that the entire motor is continuously cooled through the circulation of the cooling medium.

[0027] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0028] (1) The rotor cooling structure provided by the present invention adopts a double-layer design, dividing the rotor sheath into inner and outer layers. The micro-channel cooling structure is set only in the inner layer sheath. The design of the micro-channel cooling structure ensures that the inner layer sheath is not completely broken in the circumferential direction, minimizing the impact on the protective energy of the sheath. This allows the inner layer sheath to simultaneously undertake the functions of rotor protection and cooling, while the outer layer rotor fully undertakes the rotor protection function. The inner and outer layers sheath cooperate with each other, and the protective function of the rotor can be guaranteed without increasing or slightly increasing the sheath thickness. Since the cooling is carried out directly inside the heat source (i.e., the sheath), the rotor cooling efficiency can be effectively improved. In general, the present invention can effectively improve the rotor cooling efficiency while ensuring the protective function of the rotor sheath. It effectively solves the problems of high rotor temperature rise caused by high rotor loss and heat dissipation difficulty in high-power, high-power-density permanent magnet synchronous motors, which leads to irreversible demagnetization of permanent magnets, decreased bearing tolerance, and rotor swirl caused by thermal stress deformation.

[0029] (2) In a preferred embodiment of the present invention, cooling microchannels are designed only on the outer surface of the inner sheath. This can avoid uneven stress on the rotor permanent magnets inside the sheath due to the design of the cooling microchannels, which can generate permanent magnet debris and reduce the risk of motor performance degradation and blockage of the cooling microchannels.

[0030] (3) In a preferred embodiment of the present invention, each cooling microchannel on the outer surface of the inner sheath is a spiral microchannel, so that the other sheath portions of the layer containing the cooling microchannels form a continuous annular structure in the circumferential direction. This can improve the rotor cooling efficiency while minimizing the impact on the protective function of the sheath. In a further preferred embodiment, the cooling microchannels in the two rotor segments are symmetrically arranged about the flow divider ring, and the rotation direction of the spiral microchannels matches the rotor rotation direction. This allows the centrifugal force of the rotor at high speed to throw the cooling oil out of the end, reducing the supply demand of the external pump.

[0031] (4) In a preferred embodiment of the present invention, each cooling microchannel on the outer surface of the inner sheath is a square wave type, a sawtooth type or a sinusoidal type microchannel, which can effectively increase the contact area between the cooling medium and the heat source in each cooling microchannel and further improve the rotor cooling effect.

[0032] (5) In a preferred embodiment of the present invention, the inner sheath is further divided into layers, and the two layers of microchannels are used together to form a cooling microchannel. Based on this channel structure, after the cooling medium flows out from the guide outlet, it will fill the first microchannel, then flow into the second microchannel through the third microchannel, and then flow out through the second microchannel. This can reduce the thermal resistance of the cooling medium to the cooling source and effectively reduce the oil pump pressure, thereby further improving the rotor cooling effect. In a further preferred embodiment, an isolation protective layer is also provided between the inner sheath and the rotor segment. This can prevent the rotor permanent magnet inside the sheath from being subjected to uneven force due to the cooling microchannel design, thus avoiding the generation of permanent magnet debris and reducing the risk of the cooling microchannel being blocked. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the sheath-cooled rotor structure provided in Embodiment 1 of the present invention;

[0034] Figure 2 This is a schematic diagram of the flow divider ring in the sheath-cooled rotor structure provided in Embodiment 1 of the present invention;

[0035] Figure 3 This is a schematic diagram of the cooling flow path of the sheath-cooled rotor structure provided in Embodiment 1 of the present invention;

[0036] Figure 4 This is a schematic diagram of the sheath-cooled rotor structure provided in Embodiment 2 of the present invention;

[0037] Figure 5 This is a schematic diagram of the microchannel structure of the inner sheath of the sheath-cooled rotor structure provided in Embodiment 2 of the present invention;

[0038] Figure 6 This is a schematic diagram of the end of the sheath cooling rotor structure provided in Embodiment 2 of the present invention;

[0039] Figure 7 This is a schematic diagram of the side structure of the inner sheath of the sheath cooling rotor structure provided in Embodiment 2 of the present invention;

[0040] Figure 8 This is a partially enlarged cross-sectional view of the sheath-cooled rotor structure provided in Embodiment 2 of the present invention;

[0041] Figure 9 This is a schematic diagram of the microchannel structure of the inner sheath of the sheath-cooled rotor structure provided in Embodiment 3 of the present invention;

[0042] Figure 10This is a schematic diagram of the cooling flow path of the sheath-cooled rotor structure provided in Embodiment 3 of the present invention;

[0043] Figure 11 This is a schematic diagram of the sheath-cooled rotor structure provided in Embodiment 4 of the present invention;

[0044] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0045] 1-Flow divider ring; 12-Flow guide inlet; 13-Flow guide outlet;

[0046] 2-Rotor segment; 21-Rotor core; 22-Permanent magnet;

[0047] 3-Sheath; 31-Inner sheath; 32-Outer sheath; 33-Cooling microchannel; 34-Cooling microchannel outlet; 312-Channel layer; 313-Connecting layer; 314-First microchannel; 315-Second microchannel; 316-Third microchannel;

[0048] 4-Isolation and protective layer. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0050] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0051] Eddy current losses generated by magnets and alloy sheaths typically lead to increased rotor temperature, causing a series of problems such as permanent magnet demagnetization and rotor rubbing. To improve rotor cooling efficiency, this invention provides a sheath-cooled rotor structure and motor. The overall concept is to design a microchannel cooling structure directly within the rotor sheath, allowing the cooling medium to directly contact the heat source and reduce thermal resistance. Simultaneously, the rotor sheath is designed as a layered structure with an inner and outer sheath. Cooling microchannels that do not completely disrupt the circumference of the sheath are designed only in the inner sheath, allowing the inner sheath to simultaneously perform rotor protection and cooling functions, while the outer sheath solely performs rotor protection. This ensures both improved rotor cooling efficiency and guaranteed rotor sheath protection capabilities.

[0052] It is easy to understand that when the sheath is completely broken in the circumferential direction, it means that the axial direction at the same angular position on the circumference is completely hollowed out. This type of flow channel structure means that at that angular circumferential position, the sheath relies entirely on the non-flow channel layer of the sheath connection layer to bear the rotor's centrifugal force, while the flow channel layer of the sheath will not provide any rotor protection. As shown above, the micro-flow channel structure of this patent, where the sheath is not completely broken in the circumferential direction, can greatly reduce the disadvantages of a completely broken sheath in the circumferential direction, and achieve the reuse of rotor protection and cooling functions.

[0053] Based on the above concept, the sheath-cooled rotor structure designed in this invention includes: a rotor splitting ring and rotor segments located on both sides of the splitting ring; each rotor segment is fitted with a sheath on its outer side.

[0054] The flow divider ring is provided with N evenly distributed radial flow channels; the inner port of the radial flow channel is the flow inlet, and the outer port is the flow outlet.

[0055] The rotor segment includes: a rotor core and permanent magnets; the permanent magnets are embedded in permanent magnet slots stamped out of the rotor core.

[0056] The inner sheath is provided with N cooling microchannels extending from the flow divider ring to the axial end of the rotor; the port of the cooling microchannel in the middle of the rotor is connected to a flow guide outlet, and the port at the axial end of the rotor is the outlet of the cooling microchannel; the inner sheath is not completely interrupted by the cooling microchannel in the circumferential direction.

[0057] Where N is an integer greater than 1.

[0058] Based on the above-described cooling structure design, during operation, after the cooling medium is introduced through the shaft, it is guided by the central flow ring to flow into the cooling microchannels within the rotor's inner sheath. Through the centrifugal force of the high-speed rotation of the motor rotor and the pressure of the pump used to pump in the cooling medium, the cooling medium covers the entire inner surface of the rotor sheath along the microchannels, ultimately flowing out at both ends of the rotor's axial direction to further cool the stator end windings. The medium then collects at the bottom of the motor housing, where it is continuously cooled by circulating cooling oil. In practical applications, the cooling medium can be cooling oil or other liquid cooling media, or it can be a gaseous cooling medium.

[0059] Based on the above structural design, the present invention further designs a variety of cooling microchannel structures, which are described in detail below with reference to embodiments.

[0060] Example 1:

[0061] A sheathed cooling rotor structure, such as Figures 1-3 As shown, it includes: a flow divider ring 1 and rotor segments 2 located on both sides of the flow divider ring; each rotor segment 2 is fitted with a protective sleeve 3 on its outer side;

[0062] like Figure 2 As shown, N evenly distributed radial guide channels are provided on the flow splitting ring 1; the inner port of the radial guide channel is the guide inlet 12, and the outer port is the guide outlet 13.

[0063] like Figure 1 As shown, rotor segment 2 includes: rotor core 21 and permanent magnet 22, with permanent magnet 22 embedded in permanent magnet slots stamped out of rotor core 21.

[0064] Sheath 3 consists of an inner sheath 31 and an outer sheath 32 from the inside out;

[0065] The inner sheath 31 is provided with N cooling microchannels extending from the flow divider ring 1 to the axial end of the rotor; the port of the cooling microchannel located in the middle of the rotor is connected to a flow guide outlet 13, and the port located at the axial end of the rotor is the outlet of the cooling microchannel; the inner sheath 31 is not completely interrupted by the cooling microchannel in the circumferential direction.

[0066] The inner sheath 31 includes a flow channel layer 312 and a connecting layer 313 arranged sequentially from the inside to the outside; the cooling microchannels include a first microchannel 314 and a second microchannel 315 disposed in the flow channel layer 312, and a set of third microchannels 316 disposed in the connecting layer 313.

[0067] The first microchannel 314 extends from the shunt ring 1 toward the axial end of the rotor but does not extend to the axial end of the rotor; the second microchannel 315 extends from the axial end of the rotor toward the shunt ring 1 but does not extend to the shunt ring 1; the third microchannels 316 in the same group are parallel to each other, and the two ends of each third microchannel 316 are connected to the first microchannel 314 and the second microchannel 315 respectively.

[0068] Where N is an integer greater than 1, representing the number of parallel cooling microchannels; in practical applications, it can be set according to protection and cooling requirements.

[0069] The cooling medium in this embodiment is designed with cooling microchannels and cooling flow paths as follows: Figure 3 As shown, after the cooling medium flows out from the guide outlet, it fills the first microchannel, then flows into the second microchannel through the third microchannel, and then flows out through the second microchannel. In this parallel microchannel structure, the cooling medium arrives at the second channel in parallel, avoiding the heating process of the cooling medium through the channel path. This results in the cooling medium covering the rotor sheath surface having a lower temperature. The cooling medium flows into the second microchannel through the third microchannel and then out, which can reduce the thermal resistance of the cooling medium to the cooling source and further improve the rotor cooling effect.

[0070] Optionally, in this embodiment, the third microchannel is arranged circumferentially. In other embodiments of the present invention, the third microchannel may also have a certain angle with the circumferential direction, which can reduce the resistance of the cooling medium flowing in the cooling microchannel.

[0071] As a preferred implementation method, such as Figure 1 As shown in this embodiment, the cooling microchannels in the two rotor segments are symmetrically arranged about the flow divider ring, which can ensure that the heat dissipation of the motor rotor is balanced about the middle of the motor.

[0072] In this embodiment, since the cooling microchannels are designed directly within the heat source, the size of the cooling microchannels does not need to be excessively large to ensure effective cooling. Optionally, to minimize the impact on motor energy conversion and power output, and to avoid excessive performance degradation due to factors such as increased air gap, the thickness of the cooling microchannels in this embodiment ranges from 0.1mm to 1.5mm, and is preferably set to less than 1mm while still meeting the cooling requirements.

[0073] Example 2:

[0074] A sheathed cooling rotor structure, such as Figures 4-8 As shown, it includes: a flow divider ring 1 and rotor segments 2 located on both sides of the flow divider ring 1;

[0075] like Figure 6 As shown, N evenly distributed radial guide channels are provided on the flow splitting ring 1; the inner port of the radial guide channel is the guide inlet 12, and the outer port is the guide outlet 13.

[0076] The rotor segment 2 includes a rotor core 21 and a permanent magnet 22, with the permanent magnet 22 embedded in a permanent magnet slot stamped out of the rotor core 21.

[0077] Each rotor segment 2 is fitted with a protective sleeve on its outer side, and the protective sleeve includes an inner protective sleeve 31 and an outer protective sleeve 32 from the inside to the outside.

[0078] The outer surface of the inner sheath 31 is provided with N cooling microchannels 33 extending from the flow divider ring 1 to the axial end of the rotor; the port of the cooling microchannel located in the middle of the rotor is connected to a guide outlet 13, and the port located at the axial end of the rotor is the cooling microchannel outlet 34, such as... Figure 4 and Figure 5 As shown; the inner sheath 31 is not completely interrupted by the cooling microchannels in the circumferential direction;

[0079] Where N is an integer greater than 1.

[0080] like Figure 4 and Figure 5 As shown, in this embodiment, the cooling microchannel 33 on the outer surface of the inner sheath 31 is specifically a spiral microchannel, which makes the other sheath parts of the layer where the cooling microchannel is located form a continuous ring structure in the circumferential direction. This can improve the rotor cooling efficiency while minimizing the impact on the protective function of the sheath.

[0081] The number N of parallel cooling microchannels and the number of spiral turns K of each cooling microchannel can be set according to the protection and cooling requirements in practical applications. Optionally, in this embodiment, the number of parallel cooling microchannels is 6, and the number of spiral turns of each cooling microchannel is 1. In other embodiments of the present invention, other parameters can be set, and the number of spiral turns of each cooling microchannel does not have to be an integer.

[0082] In this embodiment, the cooling microchannels in the two rotor segments are symmetrically arranged about the flow divider ring, which ensures that the heat dissipation of the motor rotor is balanced about the middle of the motor. In addition, the rotation direction of the cooling microchannel in each rotor segment is the same as the rotation direction of the rotor. Therefore, the centrifugal force of the rotor at high speed can be used to throw the cooling oil out of the end, reducing the supply demand of the motor oil pump.

[0083] In this embodiment, since the cooling microchannels are designed directly within the heat source, the size of the cooling microchannels does not need to be excessively large to ensure cooling effectiveness. Optionally, to minimize the impact on the magnetic circuit routing and power output of the motor, the thickness of the cooling microchannels in this embodiment ranges from 0.1mm to 1.5mm, and is preferably set to less than 1mm while still meeting the cooling requirements. The cooling microchannel outlet is as follows: Figure 7 As shown, Figure 7 In the middle, the enlarged view of the part marked "M" is as follows: Figure 8 As shown. Figure 8 In the middle on the left, 'a' represents the thickness of the cooling microchannel, and 'b' represents the remaining thickness of the inner sheath after the cooling microchannel is machined.

[0084] In this embodiment, the cooling microchannels are small in size. Therefore, this embodiment sets the cooling microchannels on the outer surface of the inner sheath, which can avoid uneven force on the rotor permanent magnet inside the sheath due to the design of the cooling microchannels, thus preventing permanent magnet debris from being generated and reducing the risk of the cooling microchannels being blocked.

[0085] Example 3:

[0086] A sheath-cooled rotor structure. This embodiment is similar to Embodiment 2 above, with N cooling microchannels 33 extending from the flow-dividing ring 1 to the axial end of the rotor on the outer surface of the inner sheath 31; the port of the cooling microchannel located in the middle of the rotor is connected to a guide outlet 13, and the port located at the axial end of the rotor is the cooling microchannel outlet 34; the difference from Embodiment 2 is that in this embodiment, the cooling microchannels 33 on the outer surface of the inner sheath 31 are square wave-shaped microchannels, such as... Figure 9 As shown.

[0087] In this embodiment, the flow path of the cooling medium in the cooling microchannel is as follows: Figure 10As shown, this bent flow channel structure can effectively increase the heat dissipation area and further improve the rotor cooling efficiency while ensuring that the inner sheath is not completely broken in the circumferential direction.

[0088] In this embodiment, the specific implementation of the remaining structures can be referred to the description in Embodiment 2 above, and will not be repeated here.

[0089] Similarly, since the cooling microchannels in this embodiment are only set on the outer surface of the inner sheath, the uneven force on the rotor permanent magnet inside the sheath caused by the cooling microchannel design can be avoided, thus reducing the risk of the cooling microchannels being blocked.

[0090] Based on the same design concept, in other embodiments of the present invention, the cooling microchannel flow path can also be designed as other forms of microchannel flow path such as sawtooth or sinusoidal. The cooling microchannel groove shape can be designed as one or more of the following: arc, elliptical arc, rectangle, trapezoid, or irregular shape, as well as other forms of microchannel groove shape that include the above groove shapes plus rounded corners.

[0091] Example 4:

[0092] A sheath-cooled rotor structure. This embodiment is similar to Embodiment 1 above, except that, based on the same considerations as Embodiments 2 and 3, in order to reduce the risk of clogging of the cooling microchannels, an isolation protective layer 4 is also provided between the rotor segment and the sheath 3, so that the cooling microchannels 33 do not directly contact the rotor. Figure 11 As shown.

[0093] In this embodiment, the specific implementation of the oil distribution plate 1, the inner sheath 31, the outer sheath 32, the cooling microchannels in the inner sheath, and other structures can be referred to the description in the above embodiment 1. The flow path of the cooling medium in the cooling microchannels is also the same as in embodiment 1.

[0094] Example 5:

[0095] A permanent magnet motor includes a rotating shaft, a rotor, a stator, and a housing arranged sequentially from the inside to the outside.

[0096] The rotor is a sheath-cooled rotor structure provided in any one of embodiments 1 to 4 above;

[0097] The rotating shaft is a hollow structure with one end closed and the other end open, and N cooling medium outlets are provided in the middle, which are connected to the N radial guide channels in the rotor.

[0098] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A sheathed cooling rotor structure, characterized in that, include: The flow divider ring and rotor segments located on both sides of the flow divider ring; The diversion ring is equipped with N A uniformly distributed radial flow channel; the inner port of the radial flow channel is the flow inlet, and the outer port is the flow outlet; The rotor segment includes a rotor core and a permanent magnet; each rotor segment is fitted with a protective sleeve, which consists of an inner protective sleeve and an outer protective sleeve from the inside out. The inner sheath is provided with N A cooling microchannel extends from the flow divider ring to the axial end of the rotor; the port of the cooling microchannel located in the middle of the rotor is connected to a flow guide outlet, and the port located at the axial end of the rotor is the cooling microchannel outlet; the inner sheath is not completely interrupted by the cooling microchannel in the circumferential direction. The inner sheath includes a flow channel layer and a connecting layer arranged sequentially from the inside to the outside; the cooling microchannels include a first microchannel and a second microchannel disposed in the flow channel layer, and a set of third microchannels disposed in the connecting layer; the first microchannel extends from the flow divider ring to the axial end of the rotor but does not extend to the axial end of the rotor, and the second microchannel extends from the axial end of the rotor to the flow divider ring but does not extend to the flow divider ring; the same set of third microchannels are parallel to each other, and the two ends of each third microchannel are respectively connected to the first microchannel and the second microchannel; the sheath cooling rotor structure also includes an isolation and protective layer disposed between the rotor segment and the sheath; in, N It is an integer greater than 1.

2. The sheath-cooled rotor structure as described in claim 1, characterized in that, When the inner sheath includes a flow channel layer and a connecting layer arranged sequentially from the inside to the outside, the third microchannel is arranged along the circumferential direction or has a preset non-zero angle with the circumferential direction.

3. A permanent magnet motor, characterized in that, It includes the rotating shaft, rotor, stator and housing arranged sequentially from the inside out; The rotor is the sheath-cooled rotor structure as described in claim 1 or 2; The rotating shaft is a hollow structure that is closed at one end and open at the other, with a central section containing... N One of the rotors N Each radial flow channel corresponds to a cooling medium outlet.

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