Full-air-cooling low-loss high-speed permanent magnet rotor

Abstract

The invention discloses a full-air-cooling low-loss high-speed permanent magnet rotor. The full-air-cooling low-loss high-speed permanent magnet rotor comprises a rotor rotating shaft, a rotor iron core, surface-mounted permanent magnets and a rotor sheath, the rotor core, the surface-mounted permanent magnet and the rotor sheath are sequentially arranged on the rotor rotating shaft in the radial direction, paired supporting bearings are arranged at the two ends of the rotor rotating shaft to support the high-speed permanent magnet rotor to rotate, a first rotor shaft sleeve is arranged at one end of the rotor core, and a second rotor shaft sleeve is arranged on the side, away from the rotor core, of the rotor sheath. The second rotor shaft sleeve is connected with the rotor sheath, the second rotor shaft sleeve is provided with a differential pressure flow channel port, and the rotor core is provided with a spiral through hole. According to the rotor, gas flowing into the rotor can generate pressure differences in the axial direction and the radial direction through axial and radial structural arrangement, so that efficient cooling of the rotor is achieved, and the surface of the rotor iron core is provided with the annular grooves to further suppress eddy current loss of the surface of the iron core.

Description

Technical Field

[0001] The present invention relates to the technical field of motor equipment cooling, and more specifically, to a fully air-cooled and low-loss high-speed permanent magnet rotor. Background Art

[0002] Surface-mounted high-speed permanent magnet motors have gradually become a key link in the development of full electrification due to their characteristics of high power density, high efficiency, and low maintenance cost. As the core and key component of a high-speed permanent magnet motor, the high-speed centrifugal force and high-temperature thermal stress make the permanent magnet rotor have to face complex operating conditions. To protect the permanent magnet from damage at high speeds, the rotor sheath is mostly made of high-strength alloy or carbon fiber material. Compared with the alloy sheath, the carbon fiber sheath has advantages such as light weight and low loss, and has greater application potential in the field of high-power high-speed permanent magnet motors. However, the high speed of the rotor means that the electromagnetic field alternates at a high frequency, which will significantly increase the complexity of the electromagnetic field behavior inside the motor and pose a serious threat to the stability of the rotor's high-speed operation. On the one hand, the permanent magnet has a high conductivity and is located near the air gap region, resulting in particularly prominent electromagnetic loss problems caused by the alternating magnetic field in the air gap; on the other hand, the high rotational speed corresponds to a high peripheral linear velocity, increasing the heat generation of the high-speed wind friction loss and introducing additional temperature rise. The carbon fiber sheath has poor thermal performance. Without providing heat dissipation measures, the heat generated by the eddy current loss of the permanent magnet and the high-speed wind friction loss will accumulate inside the rotor, increasing the risk of irreversible demagnetization of the permanent magnet.

[0003] Among them, suppressing AC losses and improving heat dissipation efficiency are two effective ways to ensure the operating stability of high-speed permanent magnet rotors. For the former, permanent magnet segmentation and AC magnetic field shielding can reduce the AC losses of permanent magnets. However, the suppression of AC losses by permanent magnet segmentation is limited, and it will increase the proportion of the alternating magnetic field penetrating into the rotor core, increasing the heat generation of the rotor core; in addition, setting a metal shielding layer on the inner surface of the carbon fiber sheath will still result in large shielding layer losses and difficult heat dissipation. Forced air cooling and circulating liquid cooling are currently widely used technical means to improve the heat dissipation efficiency of the rotor. Compared with forced air cooling, circulating liquid cooling has higher heat dissipation efficiency, but also has the defects of greater viscous losses and the need for a more complex heat dissipation supporting system. The forced air cooling method has low requirements for the heat dissipation system and strong operability, and is one of the powerful alternative solutions to improve the integration of the motor system and reduce the system complexity, but it also has the technical defect of low heat dissipation efficiency. To improve the heat dissipation efficiency of forced air cooling in surface-mounted high-speed permanent magnet motors, it is still necessary to continuously optimize the rotor heat dissipation structure. Summary of the Invention

[0004] The present invention provides a high-speed permanent magnet rotor with all-air cooling and low loss. It uses a hollow shaft as the rotor shaft. By opening spiral through-holes in the rotor core, an axial cooling air flow is formed to cool the inner surface of the rotor core. In addition, pressure difference flow ports are provided on the second rotor sleeve to generate a fluid pressure difference in the radial direction, promoting the air inside the hollow shaft to flow into the rotor air gap, thereby realizing the cooling inside the rotor air gap.

[0005] The technical solution adopted by the present invention to solve its technical problems is a high-speed permanent magnet rotor with all-air cooling and low loss, which includes: a high-speed permanent magnet rotor with all-air cooling and low loss, characterized in that the high-speed permanent magnet rotor with all-air cooling and low loss includes: a rotor shaft, a rotor core, surface-mounted permanent magnets, and a rotor sheath;

[0006] The rotor core, the surface-mounted permanent magnets, and the rotor sheath are sequentially arranged on the rotor shaft in the radial direction. Both ends of the rotor shaft are provided with paired support bearings to support the rotation of the high-speed permanent magnet rotor. One end of the rotor core is provided with a first rotor sleeve, and the first rotor sleeve is connected to the rotor core. The other end of the rotor core is connected to the rotor sheath. One side of the rotor sheath away from the rotor core is provided with a second rotor sleeve, and the second rotor sleeve is connected to the rotor sheath. The second rotor sleeve is provided with pressure difference flow ports to form a radial cooling air flow for the high-speed permanent magnet rotor. The rotor core is provided with spiral through-holes to form an axial cooling air flow inside the rotor core.

[0007] Preferably, the rotor shaft includes a first shaft section, a second shaft section, and a baffle;

[0008] The first shaft section, the baffle, and the second shaft section are all connected to each other. At the connection of the first shaft section and the baffle, paired second flow channels are opened in the radial direction of the first shaft section for the radial outflow of the cooling fluid in the first shaft section. At the connection of the second shaft section and the baffle, paired first flow channels are opened in the radial direction of the second shaft section for the radial outflow of the cooling fluid in the second shaft section. One end of the first shaft section away from the baffle is provided with a first air inlet hole, and one end of the second shaft section away from the baffle is provided with a second air inlet hole, and the first air inlet hole is communicated with the second air inlet hole.

[0009] Preferably, the paired first flow channels are symmetrically distributed on both sides of the first shaft section along the central axis of the rotor shaft, and the paired second flow channels are symmetrically distributed on both sides of the second shaft section along the central axis of the rotor shaft.

[0010] Preferably, the pressure difference flow ports include a first notch and a second notch;

[0011] When the cooling gas flows, the air pressure at the first notch is higher than that at the second notch, and the air volume at the first notch is smaller than that at the second notch.

[0012] Preferably, the rotor core includes a core end plate and a core yoke;

[0013] The core end plate and the core yoke are integrally formed. The core end plate is in interference connection with the first rotor bushing. The spiral through hole is formed in the core end plate, and the spiral direction of the spiral through hole is the same as the rotation direction of the high-speed permanent magnet rotor so that the cooling medium forms an axial air flow in the spiral through hole.

[0014] Preferably, core yoke slots are evenly formed in the core yoke. Core yoke teeth are arranged between adjacent core yoke slots. The surface-mounted permanent magnets are respectively arranged on the core yoke slots and the core yoke teeth. The number of axial segments of the surface-mounted permanent magnets is equal to the total number of the core yoke teeth and the core yoke slots. The core yoke is connected to the rotor shaft. The thickness of the core yoke teeth and the surface-mounted permanent magnets arranged on the core yoke teeth is equal to the thickness of the core yoke slots and the surface-mounted permanent magnets arranged on the core yoke slots.

[0015] Preferably, triangular dividing slots are formed in the core yoke. The surface-mounted permanent magnets have the same thickness. The surface-mounted permanent magnets are attached to the core yoke, and the axial contact surfaces of adjacent surface-mounted permanent magnets correspond to the central axes of the triangular dividing slots.

[0016] Preferably, the core yoke includes a cylinder with a gradually decreasing thickness from a first end close to the core end plate to a second end far from the core end plate. A plurality of steps for attaching the surface-mounted permanent magnets are arranged on the surface of the cylinder. Step slots are arranged between adjacent steps. The sum of the thicknesses of the core yoke and the surface-mounted permanent magnets remains unchanged. The surface-mounted permanent magnet close to the first end of the core yoke has the smallest radial thickness, and the surface-mounted permanent magnet close to the second end of the core yoke has the largest radial thickness.

[0017] Preferably, an opening for connecting to the rotor shaft is formed at the end of the core yoke.

[0018] The beneficial effects of the present invention are as follows:

[0019] The present invention relates to a fully air-cooled and low-loss high-speed permanent magnet rotor. It uses a hollow shaft as the rotor shaft. By opening spiral through-holes in the rotor core, an axial cooling air flow is formed to cool the inner surface of the rotor core. In addition, pressure difference flow ports are provided on the second rotor sleeve to generate a fluid pressure difference in the radial direction, promoting the air inside the hollow shaft to flow into the rotor air gap, thus realizing the cooling inside the rotor air gap. Through the axial and radial structural settings, the gas flowing into the rotor can generate pressure differences in both the axial and radial directions to form an air flow. As a result, the fully air-cooled and low-loss high-speed permanent magnet rotor can achieve rotor cooling without additional rotor cooling auxiliary equipment, improving the rotor integration and having high heat dissipation efficiency.

[0020] Moreover, the structural setting of the rotor core forms an annular groove on its surface, blocking the eddy current path generated on the surface of the rotor core after the high-frequency magnetic field passes through the permanent magnet. On the basis of the original segmentation of the permanent magnet, the AC loss of the high-speed permanent magnet rotor assembly is further reduced.

[0021] Furthermore, compared with the liquid-cooled rotor structure, the fully air-cooled and low-loss high-speed permanent magnet rotor does not need to consider the sealing of the liquid cooling medium, and the structure is simpler and more reliable. In addition, since the liquid-cooled rotor also requires additional cooling auxiliary equipment, the complexity of the rotor cooling system is higher, and the cooling liquid has greater viscosity than air, introducing additional viscous losses generated by the liquid during the high-speed rotation of the rotor, reducing the operating efficiency of the motor system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the overall structural schematic diagram of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0023] Figure 2 is the cross-sectional structural schematic diagram of the rotor and permanent magnet of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention after assembly;

[0024] Figure 3 is the cross-sectional structural schematic diagram of the rotor shaft of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0025] Figure 4 is the end-face structural schematic diagram of the rotor core of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0026] Figure 5 is the cross-sectional structural schematic diagram of the rotor core of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention along C-C;

[0027] Figure 6 is the end-face structural schematic diagram of the second rotor sleeve of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0028] Figure 7 It is a schematic cross-sectional structure diagram of the second rotor bushing of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention along D-D;

[0029] Figure 8 It is an assembled cross-sectional profile diagram of the rotor shaft, rotor core, first bushing and second bushing of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0030] Figure 9 It is a schematic overall structure diagram of the first embodiment of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention and a flow diagram of the cooling gas;

[0031] Figure 10 It is a schematic overall structure diagram of the second embodiment of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0032] Figure 11 It is an enlarged structure diagram at A of the second embodiment of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0033] Figure 12 It is a schematic overall structure diagram of the third embodiment of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention;

[0034] Figure 13 It is an enlarged structure diagram at B of the third embodiment of the fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention.

[0035] Explanation of reference numerals: 1. Rotor shaft; 1-1. First air inlet hole; 1-2. First flow channel hole; 1-3. Second flow channel hole; 1-4. Second air inlet hole; 1-5. Baffle; 1-5-1. Axial groove;

[0036] 2. Rotor core; 2-1. Core yoke; 2-1-1. Core yoke slot; 2-1-2. Core yoke tooth; 2-1-3. Opening; 2-2. Core end plate; 2-3. Spiral through hole; 2-4. Triangular dividing groove; 2-5. Step groove;

[0037] 3. Rotor sheath;

[0038] 4. Surface-mounted permanent magnet;

[0039] 5. First rotor bushing;

[0040] 6. Support bearing;

[0041] 7. Second rotor bushing; 7-1. Pressure difference flow port; 7-2. First notch; 7-3. Second notch. Detailed implementation manners

[0042] The present invention will be further described below in conjunction with the drawings and embodiments.

[0043] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0044] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0046] As Figure 1 and Figure 2 shown, a fully air-cooled and low-loss high-speed permanent magnet rotor includes: a rotor shaft 1, a rotor core 2, surface-mounted permanent magnets 4, and a rotor sheath 3; the rotor core 2, the surface-mounted permanent magnets 4, and the rotor sheath 3 are sequentially arranged on the rotor shaft 1 in the radial direction. Both ends of the rotor shaft 1 are provided with a pair of support bearings 6 to support the rotation of the high-speed permanent magnet rotor. One end of the rotor core 2 is provided with a first rotor bushing 5, and the first rotor bushing 5 is connected to the rotor core 2. The other end of the rotor core 2 is connected to the rotor sheath 3. A second rotor bushing 7 is provided on the side of the rotor sheath 3 away from the rotor core 2, and the second rotor bushing 7 is connected to the rotor sheath 3. A differential pressure flow port 7-1 is provided on the second rotor bushing 7 to form a radial cooling air flow for the high-speed permanent magnet rotor. A spiral through hole 2-3 is provided in the rotor core 2 to form an axial cooling air flow inside the rotor core 2.

[0047] In this embodiment, the rotor shaft 1 of the fully air-cooled low-loss high-speed permanent magnet rotor is a hollow shaft, and spiral through holes 2-3 are formed in the rotor core 2, so that when external gas flows into the hollow shaft, an axial fluid pressure difference can be formed to cool the inner surface of the rotor core 2. A differential pressure flow port 7-1 is arranged on the rotor sleeve, and the radially centrifugal structure arranged at the differential pressure flow port 7-1 can directly introduce external cooling air into the rotor air gap, and realize the cooling inside the rotor through the air gap inside the rotor and can cool and dissipate heat from the surface of the sheath at the same time. Through the axial and radial structural settings, the fully air-cooled low-loss high-speed permanent magnet rotor enables the gas flowing into the rotor to generate pressure differences in both the axial and radial directions, thereby forming an air flow. Furthermore, the fully air-cooled low-loss high-speed permanent magnet rotor can achieve rotor cooling without additional rotor cooling auxiliary equipment, improving the integration of the rotor and having high heat dissipation efficiency. The setting of the support bearing 6 further provides support for the high-speed rotation of the rotor. Moreover, the first rotor sleeve 5 and the second rotor sleeve 7 have the functions of axial limit and dynamic balance weight removal, avoiding the movement of the rotor core 2 and the rotor sheath 3 under high-speed movement, effectively ensuring the stability of the rotor, and guaranteeing the quality and service life of the rotor.

[0048] See Figure 3 , the rotor shaft 1 includes a first shaft section, a second shaft section and a baffle 1-5; the first shaft section, the baffle 1-5 and the second shaft section are all connected to each other. At the connection between the first shaft section and the baffle 1-5, paired second flow channels 1-3 are formed in the radial direction of the first shaft section for the radial outflow of the cooling fluid in the first shaft section. At the connection between the second shaft section and the baffle 1-5, paired first flow channels 1-2 are formed in the radial direction of the second shaft section for the radial outflow of the cooling fluid in the second shaft section. A first air inlet hole 1-1 is formed at one end of the first shaft section away from the baffle 1-5, and a second air inlet hole 1-4 is formed at one end of the second shaft section away from the baffle 1-5. The first air inlet hole 1-1 is communicated with the second air inlet hole 1-4. The paired first flow channels 1-2 are symmetrically distributed on both sides of the first shaft section along the central axis of the rotor shaft 1, and the paired second flow channels 1-3 are symmetrically distributed on both sides of the second shaft section along the central axis of the rotor shaft 1. In a preferred embodiment, an axial groove 1-5-1 is arranged on the baffle 1-5, and the axial groove 1-5-1 is used for mating connection with the rotor core 2.

[0049] In this embodiment, both the first air inlet hole 1-1 and the second air inlet hole 1-4 are axial holes and both serve as the inlets for the rotor cooling gas. The external cooling gas enters the rotor interior through the first air inlet hole 1-1 and the second air inlet hole 1-4, and then transfers and flows in the radial direction inside the rotor through the first flow channel hole 1-2 and the second flow channel hole 1-3, so as to enter the rotor air gap interior, and the cooling inside the rotor can be realized through the air gap in the rotor, and at the same time, the surface of the sheath can be cooled and dissipated of heat. The first flow channel hole 1-2 and the second flow channel hole 1-3 are symmetrically distributed on both sides of the rotor shaft 1 and on both sides of the baffle 1-5, which can further effectively reduce the influence of uneven distribution of the cooling air flow caused by different pressures in the shaft cavity on the rotor heat dissipation and improve the heat dissipation efficiency.

[0050] As Figures 6 - 8 shown, the differential pressure flow port 7-1 includes a first notch 7-2 and a second notch 7-3; when the cooling gas flows, the air pressure at the first notch 7-2 is higher than that at the second notch 7-3, and the air volume at the first notch 7-2 is smaller than that at the second notch 7-3. In a preferred embodiment, the differential pressure flow port 7-1 has a structure similar to that of a centrifugal fan blade; the differential pressure flow port 7-1 includes a first notch 7-2 and a second notch 7-3, and the structure of the differential pressure flow port 7-1 is designed according to the rotation direction of the rotor, always making the cooling fluid flow from the first notch 7-2 to the second notch, that is, the pressure at the first notch 7-2 is greater than the pressure at the second notch 7-3. When the rotor rotates at a high speed, the cooling fluid inside the rotor shaft 1 will flow into the air gap of the rotor under the action of the differential pressure, dissipate the heat generated by the high-speed wind friction loss, reduce the risk of the heat of the wind friction loss accumulating on the surface of the sheath, and is more conducive to the safe and reliable operation of the high-speed permanent magnet rotor. And the second rotor shaft sleeve 7 further includes an interference fit surface assembled with the rotor shaft 1 for restricting the axial displacement of the second rotor shaft sleeve 7 on the rotor axis and preventing the second rotor shaft sleeve 7 from axially moving. In addition, the second rotor shaft sleeve 7 further includes a weight removal surface for correcting the dynamic unbalance of the rotor assembly.

[0051] See Figure 4 and Figure 5 as shown, the rotor core 2 includes a core end plate 2-2 and a core yoke 2-1; the core end plate 2-2 and the core yoke 2-1 are integrally formed, the core end plate 2-2 is in interference connection with the first rotor shaft sleeve 5, and a spiral through hole 2-3 is formed in the core end plate 2-2, and the spiral direction of the spiral through hole 2-3 is the same as the rotation direction of the high-speed permanent magnet rotor so that the cooling medium forms an axial air flow in the spiral through hole 2-3.

[0052] In this embodiment, the spiral direction of the spiral through-hole 2-3 is determined by the rotation direction of the rotor, which is used to generate an axial pressure difference to form an axial air flow, thereby cooling the inner surface of the rotor core 2. The inner circular surface of the core end plate 2-2 is assembled with the core mating surface of the rotor core 2, and an interference connection is adopted to achieve torque transmission. At the same time, an opening 2-1-3 connected to the rotor shaft 1 is provided at the end of the core yoke, and the opening 2-1-3 is assembled with the axial groove 1-5-1 in the baffle 1-5, so as to realize the axial positioning of the rotor core 2.

[0053] Under the above structural configuration, referring to Figure 9 , the basic principle of the fully air-cooled rotor is as follows:

[0054] When the rotor rotates at a high speed, the spiral through-hole 2-3 in the rotor core 2 will generate an axial pressure difference, forcing the air inside the hollow shaft to flow axially along the inner surface of the rotor core 2 from the first flow channel hole 1-2 and the second flow channel hole 1-3, and at the same time flowing out from the spiral through-hole 2-3, so as to realize the cooling of the inner surface of the rotor core 2.

[0055] In addition, under the action of the radial pressure difference generated by the pressure difference flow port 7-1 in the second rotor sleeve 7, the cooling fluid inside the shaft will flow into the pressure difference flow port 7-1 from the second flow channel hole 1-3 of the shaft and enter the rotor air gap to dissipate the heat in the air gap.

[0056] According to the above rotor structure, in a fully air-cooled and low-loss high-speed permanent magnet rotor of the present invention, the core yoke 2-1 includes various embodiments that can effectively achieve the above rotor cooling method. The present invention provides the following embodiments, and the technical features of each of the following embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described.

[0057] Embodiment 1: As Figure 9 shown, in a preferred embodiment, core yoke grooves 2-1-1 are evenly provided on the core yoke 2-1, core yoke teeth 2-1-2 are provided between adjacent core yoke grooves 2-1-1, surface-mounted permanent magnets 4 are arranged in one-to-one correspondence on the core yoke grooves 2-1-1 and the core yoke teeth 2-1-2, the number of axial segments of the surface-mounted permanent magnets is equal to the sum of the number of core yoke teeth 2-1-2 and core yoke grooves 2-1-1, the core yoke 2-1 is connected to the rotor shaft 1, and the thickness of the core yoke teeth 2-1-2 and the surface-mounted permanent magnets provided on the core yoke teeth 2-1-2 is equal to the thickness of the surface-mounted permanent magnets provided on the core yoke grooves 2-1-1 and the core yoke grooves 2-1-1.

[0058] In this embodiment, the rotor sheath 3 is preferably made of high-strength carbon fiber composite material wound under high tension to ensure that a pre-pressure sufficient to counteract the high-speed centrifugal force is provided for the permanent magnet. The surface-mounted permanent magnet 4 is in an axially segmented form, and the number of segments is equal to the sum of the number of core slots and core teeth in the rotor core 2.

[0059] In this embodiment, on the one hand, the segmented surface-mounted permanent magnets 4 with different thicknesses can equivalently increase the magnetic load of the motor, reduce the direct and quadrature axis synchronous reactance, and improve the motor load output capacity and operating power factor; on the other hand, the axial segmentation of the permanent magnets can reduce the influence of the air-gap magnetic field on the eddy current loss inside them, and by providing the core yoke teeth 2-1-2 and core yoke slots 2-1-1 on the outer circumferential surface of the rotor core 2 in the present invention, the eddy current loss generated by the high-frequency components of the current time harmonics inside the rotor core 2 can also be reduced, further reducing the heat generation of the rotor assembly and improving the degree of suppression of electromagnetic losses in the rotor assembly. The surface of the rotor core 2 is arranged in the form of circumferential grooves, which can further suppress the eddy current loss inside the rotor core 2, and there is no need to set up a shielding layer to transfer the eddy current inside the permanent magnet.

[0060] Embodiment 2: Refer to Figure 10 and Figure 11 , a triangular segmentation groove 2-4 is provided on the core yoke 2-1, the surface-mounted permanent magnets are of equal thickness, and the surface-mounted permanent magnets are attached to the core yoke 2-1 and the axial contact surfaces of adjacent surface-mounted permanent magnets correspond to the central axis of the triangular segmentation groove 2-4.

[0061] In this embodiment, the suppression of the eddy current loss on the surface of the rotor core 2 is achieved through the setting of the triangular segmentation groove 2-4, while ensuring that the radial thicknesses of the segmented permanent magnets are equal. And since the radial thicknesses of the segmented permanent magnets are equal, there is no need to put forward additional requirements for the winding of the rotor sheath 3, which is the same as the winding method of the sheath of the traditional surface-mounted permanent magnet rotor and has the characteristics of simple processing. Further, in order to ensure that the introduction of the segmentation groove does not have an obvious impact on the electromagnetic performance of the rotor, in a preferred embodiment, the triangular segmentation groove 2-4 is set as a slender triangular structure, that is, it has a relatively large groove depth but a relatively small width. As shown in the figure, the smaller the ratio of the bottom side length of the triangular segmentation groove to the axial length of the rotor, the better, which is approximately the same as the way of cutting the eddy current path by laminating the stator of a conventional motor, and it only needs to achieve the equivalent "path segmentation" effect.

[0062] Embodiment 3: Refer to Figure 12 and Figure 13, the iron core yoke 2-1 includes a cylinder with a gradually decreasing thickness from the first end close to the iron core end plate 2-2 towards the second end away from the iron core end plate 2-2. Multiple steps for attaching surface-mounted permanent magnets are provided on the surface of the cylinder, and a step groove 2-5 is provided between adjacent steps. The sum of the thicknesses of the iron core yoke 2-1 and the surface-mounted permanent magnets remains unchanged. The surface-mounted permanent magnet near the first end of the iron core yoke 2-1 has the smallest radial thickness, and the surface-mounted permanent magnet near the second end of the iron core yoke 2-1 has the largest radial thickness.

[0063] In this embodiment, it has an axially stepped iron core surface. The preferred permanent magnet pasting process is axially inserted. The surface-mounted permanent magnet 4 can be accurately positioned through the axially stepped iron core yoke 2-1.

[0064] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0065] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A fully air-cooled, low-loss, high-speed permanent magnet rotor, characterized in that: The fully air-cooled, low-loss high-speed permanent magnet rotor comprises: a rotor shaft, a rotor core, a surface-mounted permanent magnet and a rotor sleeve; The rotor core, surface-mounted permanent magnets and rotor sleeve are sequentially arranged on the rotor shaft along the radial direction. Pairs of support bearings are arranged at both ends of the rotor shaft to support the rotation of the high-speed permanent magnet rotor. A first rotor sleeve is arranged at one end of the rotor core, and the first rotor sleeve is connected to the rotor core. The other end of the rotor core is connected to the rotor sleeve. A second rotor sleeve is arranged on the side of the rotor sleeve away from the rotor core, and the second rotor sleeve is connected to the rotor sleeve. A pressure difference flow channel opening is arranged on the second rotor sleeve so that the high-speed permanent magnet rotor forms a radial cooling airflow. A spiral through hole is opened on the rotor core so that an axial cooling airflow is formed in the rotor core.

2. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 1 is characterized in that: The rotor shaft comprises a first shaft section, a second shaft section and a baffle; The first shaft segment, the baffle and the second shaft segment are all connected to each other. A pair of second flow channel holes are opened at the connection between the first shaft segment and the baffle along the radial direction of the first shaft segment for radial outflow of cooling fluid in the first shaft segment. A pair of first flow channel holes are opened at the connection between the second shaft segment and the baffle along the radial direction of the second shaft segment for radial outflow of cooling fluid in the second shaft segment. A first air inlet hole is opened at one end of the first shaft segment away from the baffle, and a second air inlet hole is opened at one end of the second shaft segment away from the baffle, and the first air inlet hole is communicated with the second air inlet hole.

3. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 2 is characterized in that: The paired first flow channel holes are symmetrically distributed on both sides of the first shaft section along the central axis of the rotor shaft, and the paired second flow channel holes are symmetrically distributed on both sides of the second shaft section along the central axis of the rotor shaft.

4. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 1, characterized in that: The pressure difference flow channel opening includes a first notch and a second notch; When the cooling gas flows, the air pressure of the first slot is higher than the air pressure of the second slot, and the air volume of the first slot is smaller than the air volume of the second slot.

5. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 1, characterized in that: The rotor core comprises a core end plate and a core yoke; The core end plate and the core yoke are integrally formed, the core end plate is interference-connected with the first rotor sleeve, the core end plate is provided with the spiral through hole, the spiral direction of the spiral through hole is the same as the rotation direction of the high-speed permanent magnet rotor so that the cooling medium forms an axial airflow in the spiral through hole.

6. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 5, characterized in that: The core yoke is evenly provided with core yoke grooves, and core yoke teeth are arranged between adjacent core yoke grooves. The surface-mounted permanent magnets are arranged on the core yoke grooves and the core yoke teeth in a one-to-one correspondence, and the number of axial segments of the surface-mounted permanent magnets is equal to the sum of the number of the core yoke teeth and the core yoke grooves. The core yoke is connected to the rotor shaft, and the core yoke teeth and the core yoke grooves are attached with the surface-mounted permanent magnets of unequal radial thicknesses, and the radius of the core yoke teeth after the surface-mounted permanent magnets are attached is equal to the radius of the core yoke grooves after the surface-mounted permanent magnets of different thicknesses are attached.

7. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 5, characterized in that: The core yoke is provided with a triangular dividing groove, the surface-mounted permanent magnets have uniform thickness, the surface-mounted permanent magnets are attached to the core yoke, and the axial contact surfaces of adjacent surface-mounted permanent magnets correspond to the central axis of the triangular dividing groove.

8. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 5, characterized in that: The core yoke portion includes a cylinder whose thickness gradually decreases from a first end close to the core end plate toward a second end away from the core end plate. A plurality of steps for attaching the surface-mounted permanent magnet are provided on the surface of the cylinder, and step grooves are provided between adjacent steps. The sum of the thickness of the core yoke portion and the surface-mounted permanent magnet remains unchanged. The surface-mounted permanent magnet close to the first end of the core yoke portion has the smallest radial thickness, and the surface-mounted permanent magnet close to the second end of the core yoke portion has the largest radial thickness.

9. The fully air-cooled, low-loss, high-speed permanent magnet rotor according to claim 5, characterized in that: An opening connected to the rotor shaft is formed at the end of the core yoke.

Images