Rotor for high-speed permanent magnet motor

Abstract

The invention discloses a rotor for a high-speed permanent magnet motor. The rotor for the high-speed permanent magnet motor comprises a rotor assembly and paired support bearings, the rotor assembly comprises a permanent magnet sheath, a surface-mounted permanent magnet, a rotor core and paired rotor shaft sections, and the rotor core, the surface-mounted permanent magnet and the permanent magnet sheath are coaxially sleeved one by one along the radial direction of the rotor assembly; the paired rotor shaft sections are respectively arranged at the two ends of the rotor assembly and are connected with the rotor core, the surface-mounted permanent magnets and the permanent magnet sheaths, the paired support bearings are respectively positioned at the two ends of the rotor assembly and are connected with the paired rotor shaft sections in a one-to-one correspondence manner, and a cooling medium runner is arranged in the rotor core. According to the rotor, the eddy current conduction path in the permanent magnet is cut off in the circumferential direction and the axial direction through the segmented structure, so that the eddy current loss is weakened, and the calorific value of the rotor is reduced. In addition, the space where the interelectrode filler is located is fully utilized for arranging the cooling medium flow channel, the heat dissipation efficiency is further improved, and the structure is simplified.

Description

Technical Field

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

[0002] Compared with an interior permanent magnet rotor, a surface-mounted permanent magnet rotor is widely used in the field of high-speed motors mainly because of its stronger air-gap magnetic field, higher structural strength, and simpler topological structure. In applications with low power ratings, the sheath of the surface-mounted permanent magnet rotor is mostly made of high-strength alloy materials. However, the complex air-gap synthetic magnetic field will generate eddy current losses in the alloy sheath, resulting in a large amount of heat generation in the rotor. In severe cases, irreversible demagnetization of the permanent magnet will occur. In applications with high speed and high power, in order to improve the protection effect of the rotor sheath on the permanent magnet and reduce the AC losses inside the sheath, carbon fiber sheaths with high strength and low electrical conductivity are mostly used. However, the carbon fiber sheath is a poor heat conductor, and the high-speed wind friction loss will cause heat to accumulate inside the rotor. Moreover, the high-frequency components in the current time harmonics will generate serious eddy current losses inside the permanent magnet, further aggravating the heat generation of the rotor and reducing the operating reliability of the permanent magnet.

[0003] To reduce the risk of high-temperature demagnetization of the permanent magnet, two main measures are considered, namely, suppressing the eddy current loss of the permanent magnet and improving the heat dissipation efficiency of the rotor. In terms of suppressing eddy current loss, increasing the number of segments of the permanent magnet along the eddy current conduction direction can cut off the eddy current conduction path inside the permanent magnet, weaken the eddy current loss, and reduce the heat generation of the rotor. However, excessive increasing of the number of segments of the permanent magnet will additionally increase the complexity of the rotor assembly, and the degree of suppression of the eddy current loss is limited. At the same time, it cannot reduce the heat generated by the high-speed wind friction loss, limiting the application potential of this method. In terms of improving the heat dissipation efficiency of the rotor, existing methods mostly adopt forced air cooling or liquid cooling methods to suppress the temperature rise in its high-speed state. Forced air cooling has simple requirements for auxiliary heat dissipation equipment and has good feasibility. However, the permanent magnet is wrapped by the sheath inside the rotor, and forced air cooling can only dissipate the heat caused by the wind friction loss on the surface of the sheath, and it is difficult to take into account the heat generated by the eddy current loss inside the permanent magnet, so the cooling effect is limited. Compared with forced air cooling, the cooling fluid in liquid cooling directly contacts the rotor, has a larger specific heat than the cooling gas, and can achieve efficient heat dissipation of the rotor. For example, patent (publication number: CN118300314A) discloses a liquid cooling topology for a surface-mounted permanent magnet rotor, which can achieve efficient heat dissipation of the rotor. However, additional cooling channels and flow guiding plates need to be added in this topology, increasing the structural complexity of the high-speed permanent magnet rotor assembly and increasing the risk of failure during operation. Summary of the Invention

[0004] The present invention provides a rotor for a high-speed permanent magnet motor, which uses the space where the filler between the permanent magnet poles is located as the cooling flow channel of the rotor core, simplifies the existing rotor heat dissipation structure, reduces the weight of the rotor under the condition of maintaining the same rotor structure shape, and improves the heat dissipation effect of the cooling medium on the rotor.

[0005] The technical solution adopted by the present invention to solve its technical problems is a rotor for a high-speed permanent magnet motor, which includes: a rotor assembly and a pair of supporting bearings;

[0006] The rotor assembly includes a permanent magnet sheath, surface-mounted permanent magnets, a rotor core, and a pair of rotor shaft segments. The rotor core, surface-mounted permanent magnets, and permanent magnet sheath are coaxially sleeved one by one along the radial direction of the rotor assembly. The pair of rotor shaft segments are respectively arranged at both ends of the rotor assembly and are both connected to the rotor core, surface-mounted permanent magnets, and permanent magnet sheath. The pair of supporting bearings are respectively located at both ends of the rotor assembly and are correspondingly connected to the pair of rotor shaft segments one by one.

[0007] Preferably, the rotor core includes a first rotor core and a second rotor core. The first rotor core is sleeved outside the second rotor core, and the first rotor core and the second rotor core are connected.

[0008] Preferably, the first rotor core includes a first core body and a pair of core teeth;

[0009] The pair of core teeth are evenly distributed in a circumferential direction on the first core body. The surface-mounted permanent magnets are evenly attached between adjacent core teeth so that a pair of pole regions are formed between adjacent core teeth. Tooth portion flow channels penetrating in the axial direction of the first rotor core are provided on the core teeth. Circumferentially evenly distributed core vent holes are provided on the axial end surface of the first core body, and the core vent holes and the tooth portion flow channels are circumferentially staggered.

[0010] Preferably, the second rotor core includes a core joint matching the core teeth and a second core body;

[0011] The core joints are evenly arranged at the end of the second core body and correspond to the core teeth. Core flow channels communicating with the tooth portion flow channels are provided on the core joints for the circulation of the cooling medium. The first core body and the second core body are connected with an interference fit, and the first core body and the second core body are respectively connected to the rotor shaft segments.

[0012] Preferably, shaft segment vent holes are provided on the rotor shaft segments, and the shaft segment vent holes match the core vent holes so that the rotor core communicates with the outside to balance the air pressure.

[0013] Preferably, a shaft segment groove is further formed on the rotor shaft segment, notch openings matching with the shaft segment groove are arranged on both the first iron core body and the second iron core body, and the shaft segment groove is clamped with the notch openings.

[0014] Preferably, shaft segment through-holes are formed on paired rotor shaft segments, the shaft segment through-holes are respectively communicated with the tooth part flow channel and the iron core flow channel, the shaft segment through-hole communicating with the tooth part flow channel is used for the inflow of the cooling medium, and the shaft segment through-hole communicating with the iron core flow channel is used for the outflow of the cooling medium.

[0015] Preferably, the surface-mounted permanent magnets are arranged in segments along the axial direction of the rotor iron core, and the pole arc coefficient of the surface-mounted permanent magnets is less than 1.

[0016] The beneficial effects of the present invention are as follows:

[0017] In the present invention, a rotor for a high-speed permanent magnet motor uses the space where the fillers between the permanent magnet poles are located as the cooling flow channel of the rotor iron core, simplifies the existing rotor heat dissipation structure, reduces the weight of the rotor under the condition of maintaining the shape of the rotor structure unchanged, and improves the heat dissipation effect of the cooling medium on the rotor at the same time. It makes full use of the space between the magnetic poles, sets an axial cooling flow channel, enables the cooling fluid to be as close to the permanent magnet as possible directly, has a better heat dissipation effect, and avoids additionally increasing the auxiliary structure of the cooling flow channel, realizing the simplification, integration and high-efficiency heat dissipation of the structure.

[0018] Moreover, the rotor is arranged as a segmented structure in the axial direction, thereby effectively reducing the eddy current loss of the permanent magnet and further reducing the heat generation of the rotor. And, the surface-mounted permanent magnets are arranged in segments in the circumferential direction of the iron core, so that the rotor for the high-speed permanent magnet motor is also a segmented structure in the circumferential direction, thereby further cutting off the eddy current conduction path inside the permanent magnet in the circumferential direction, realizing the weakening of the eddy current loss and reducing the heat generation of the rotor. The rotor for the high-speed permanent magnet motor, through the segmented structure arrangement in the circumferential and axial directions, effectively cuts off the eddy current conduction path inside the permanent magnet, realizes the weakening of the eddy current loss, reduces the heat generation of the rotor, and at the same time avoids the increase in the complexity of the rotor assembly caused by excessively increasing the number of segments of the permanent magnet in a single direction. Description of the Drawings

[0019] Figure 1 is the overall structural schematic diagram of the rotor for the high-speed permanent magnet motor of the present invention;

[0020] Figure 2 is the structural schematic diagram of the rotor assembly of the rotor for the high-speed permanent magnet motor of the present invention;

[0021] Figure 3 is the radial structural schematic diagram of the rotor assembly of the rotor for the high-speed permanent magnet motor of the present invention;

[0022] Figure 4 It is a schematic cross-sectional structure diagram of the rotor assembly of the rotor for the high-speed permanent magnet motor of the present invention along the radial direction B-B;

[0023] Figure 5 It is a schematic structural diagram of the first rotor core of the rotor for the high-speed permanent magnet motor of the present invention

[0024] Figure 6 It is a schematic structural diagram of the second rotor core of the rotor for the high-speed permanent magnet motor of the present invention;

[0025] Figure 7 It is a schematic cross-sectional diagram of the rotor core flow channel of the rotor for the high-speed permanent magnet motor of the present invention;

[0026] Figure 8 It is a schematic structural diagram of the assembly of the first rotor core and the second rotor core of the rotor for the high-speed permanent magnet motor of the present invention;

[0027] Figure 9 It is a schematic structural diagram of the rotor shaft section of the rotor for the high-speed permanent magnet motor of the present invention;

[0028] Figure 10 It is a schematic cross-sectional structure diagram of the rotor shaft section of the rotor for the high-speed permanent magnet motor of the present invention;

[0029] Figure 11 It is a schematic three-dimensional assembly axial cross-sectional structure diagram of the rotor for the high-speed permanent magnet motor of the present invention.

[0030] Explanation of reference numerals: 1. Rotor assembly; 1-1. Rotor shaft section; 1-1-1. Axial section vent hole; 1-1-2. Axial section groove; 1-1-3. Axial section through hole;

[0031] 2. Permanent magnet sheath; 3. Support bearing; 3-1. First support bearing; 3-2. Second support bearing;

[0032] 4. Surface-mounted permanent magnet; 4-1. First magnetic pole; 4-2. Second magnetic pole; 4-3. Third magnetic pole; 4-4. Fourth magnetic pole;

[0033] 5. Rotor core; 5-1. First rotor core; 5-1-1. Core vent hole; 5-1-2. Tooth part flow channel; 5-1-3. Core tooth; 5-2. Second rotor core; 5-2-1. Core flow channel; 5-2-2. Core joint. Detailed implementation manners

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] 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 practiced 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.

[0036] 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. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill 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.

[0038] As Figure 1 and Figure 2 shown, a rotor for a high-speed permanent magnet motor includes: a rotor assembly 1 and a pair of support bearings 3; the rotor assembly 1 includes a permanent magnet sheath 2, surface-mounted permanent magnets 4, a rotor core 5, and a pair of rotor shaft segments 1-1. The rotor core 5, the surface-mounted permanent magnets 4, and the permanent magnet sheath 2 are coaxially sleeved one by one along the radial direction of the rotor assembly 1. The pair of rotor shaft segments 1-1 are respectively arranged at both ends of the rotor assembly 1 and are both connected to the rotor core 5, the surface-mounted permanent magnets 4, and the permanent magnet sheath 2. The pair of support bearings 3 are respectively located at both ends of the rotor assembly 1 and are correspondingly connected to the pair of rotor shaft segments 1-1. A cooling medium flow channel is provided in the rotor core 5.

[0039] In this embodiment, the rotor for the high-speed permanent magnet motor is arranged as a segmented structure in the axial direction, thus effectively reducing the eddy current loss of the permanent magnet and further reducing the heat generation of the rotor. Moreover, the surface-mounted permanent magnets make the rotor for the high-speed permanent magnet motor also a segmented structure in the circumferential direction, thereby further cutting off the eddy current conduction path inside the permanent magnet in the circumferential direction, achieving the weakening of the eddy current loss and reducing the heat generation of the rotor. The rotor for the high-speed permanent magnet motor effectively cuts off the eddy current conduction path inside the permanent magnet through the segmented structure in the circumferential and axial directions, realizes the weakening of the eddy current loss, reduces the heat generation of the rotor, and at the same time avoids the increase in the complexity of the rotor assembly 1 caused by excessive increase in the number of segments of the permanent magnet in a single direction. Further, the rotor for the high-speed permanent magnet motor utilizes the space where the permanent magnet inter-pole filler is located in the rotor core 5 to set up a cooling medium flow channel, which further improves the heat dissipation efficiency of the rotor and simplifies the rotor structure, avoiding the complication of the rotor structure.

[0040] Moreover, there is no limitation on the material of the rotor sheath in the rotor for the high-speed permanent magnet motor. It can be a carbon fiber sheath with light weight, high strength and low conductivity, or an alloy metal sheath, depending on the use scenario. The rotor assembly 1 is a hollow structure as a whole to achieve the purpose of light weight. The paired support bearings 3 include a first support bearing 3-1 and a second support bearing 3-2, which are respectively arranged on the left and right sides of the rotor assembly 1 and are used as the rotational support of the rotor.

[0041] As Figures 3 - 8 shown, the rotor core 5 includes a first rotor core 5-1 and a second rotor core 5-2. The first rotor core 5-1 is sleeved outside the second rotor core 5-2, and the first rotor core 5-1 and the second rotor core 5-2 are connected.

[0042] Among them, the first rotor core 5-1 includes a first core body and a pair of core teeth 5-1-3; the pair of core teeth 5-1-3 are evenly distributed in a circumferential manner on the first core body. The surface-mounted permanent magnets 4 are evenly attached between the adjacent core teeth 5-1-3 so that a pair of pole regions are formed between the adjacent core teeth 5-1-3. Tooth-shaped flow channels 5-1-2 penetrating in the axial direction of the first rotor core 5-1 are provided on the core teeth 5-1-3, and circumferentially evenly distributed core vent holes 5-1-1 are provided on the axial end surface of the first core body. The core vent holes 5-1-1 and the tooth-shaped flow channels 5-1-2 are circumferentially offset.

[0043] The second rotor core 5-2 includes a core joint 5-2-2 that mates with the core teeth 5-1-3 and a second core body; the core joints 5-2-2 are evenly arranged at the ends of the second core body and correspond to the core teeth 5-1-3. Core flow channels 5-2-1 communicating with the tooth flow channels 5-1-2 are provided on the core joints 5-2-2 for the circulation of the cooling medium. The first core body and the second core body are connected with an interference fit, and the first core body and the second core body are respectively connected to the rotor shaft section 1-1.

[0044] In this embodiment, the rotor core 5 of the high-speed permanent magnet motor makes full use of the inter-pole gap of the permanent magnet. By arranging the core teeth 5-1-3, the space where the traditional inter-pole filler is located is fully utilized as the cooling channel for the rotor cooling medium. Setting the cooling channel in the space where the filler is located will not increase the structural complexity of the rotor, and there is no need to introduce additional auxiliary structures to protect the rotor. At the same time, it has no significant impact on the mechanical and electromagnetic properties of the rotor, enabling the rotor of the high-speed permanent magnet motor to reduce the cooling complexity and cooling cost of the rotor on the premise of efficiently cooling the rotor. Among them, the radial cross-sectional shape of the tooth flow channel 5-1-2 is indefinite and can be other shapes such as rectangular or circular.

[0045] Furthermore, the segmented setting of the rotor core in the present invention is considered for the feasibility of the actual processing technology, rather than for the sake of segmentation. If the rotor core can be processed by a one-time processing method, a direct integral structure of the rotor core will have better effects.

[0046] In a preferred embodiment, shaft section vent holes 1-1-1 are provided on the rotor shaft sections 1-1. The shaft section vent holes 1-1-1 are matched with the core vent holes 5-1-1 to enable the rotor core 5 to communicate with the outside to balance the air pressure. In this embodiment, the shaft section vent holes 1-1-1 and the core vent holes 5-1-1 have the same number in the circumferential direction, and the radial radius and circumferential angle of the holes are the same, which are used to connect the inside of the rotor core 5 cavity with the outside atmosphere to prevent sudden changes in the pressure inside the rotor core 5, thereby affecting the high-speed running stability of the rotor.

[0047] See Figures 9 - 10 , shaft section grooves 1-1-2 are also provided on the rotor shaft sections 1-1. Notch openings matching the shaft section grooves 1-1-2 are provided on the first core body and the second core body, and the shaft section grooves 1-1-2 are snap-connected with the notch openings. Shaft section through holes 1-1-3 are provided on the paired rotor shaft sections 1-1. The shaft section through holes 1-1-3 are respectively communicated with the tooth flow channels 5-1-2 and the core flow channels 5-2-1. The shaft section through holes 1-1-3 communicating with the tooth flow channels 5-1-2 are used for the inflow of the cooling medium, and the shaft section through holes 1-1-3 communicating with the core flow channels 5-2-1 are used for the outflow of the cooling medium.

[0048] In this embodiment, the mating and clamping of the shaft segment groove 1-1-2 and the notch can effectively restrict the displacement of the rotor shaft segment 1-1, avoid the axial movement of the rotor shaft segment 1-1 during use, and effectively prevent the failure of the rotor torque transmission. The setting of the shaft segment through-hole 1-1-3 can be used for the inflow and outflow of the cooling medium, enabling the rotor for the high-speed permanent magnet motor to achieve rapid cooling.

[0049] In a preferred embodiment, the surface-mounted permanent magnets 4 are arranged in segments along the axial direction of the rotor core 5, and the pole arc coefficient of the surface-mounted permanent magnets 4 is less than 1. In order to reserve an axial cooling space between the poles of the permanent magnets, the pole arc coefficient of the permanent magnets needs to be less than 1. Moreover, the magnetization method of a single pole of the permanent magnet can be arbitrarily selected. For example, radial magnetization, parallel magnetization, or Halbach magnetization can all be used. In one embodiment, as Figure 4 shown, taking the number of pole pairs of the permanent magnet as 2 as an example, the surface-mounted permanent magnets 4 are divided into four parts on the circumference, and each part forms a pole. For example, 4-1 is the first magnetic pole, 4-2 is the second magnetic pole, 4-3 is the third magnetic pole, and 4-4 is the fourth magnetic pole. The above four poles together form a 2-pole topology of the rotor assembly 1, and there is an iron core tooth 5-1-3 between adjacent magnetic poles so that the cooling medium can quickly dissipate the heat during the operation of the magnetic poles.

[0050] 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 as the scope described in this specification.

[0051] 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 deformations 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 rotor for a high-speed permanent magnet motor, characterized in that: The rotor for the high-speed permanent magnet motor comprises: a rotor assembly and a pair of supporting bearings; The rotor assembly includes a permanent magnet sleeve, a surface-mounted permanent magnet, a rotor core and a pair of rotor shaft segments. The rotor core, the surface-mounted permanent magnet and the permanent magnet sleeve are coaxially sleeved one by one along the radial direction of the rotor assembly. The paired rotor shaft segments are respectively arranged at both ends of the rotor assembly and are connected to the rotor core, the surface-mounted permanent magnet and the permanent magnet sleeve. The paired support bearings are respectively located at both ends of the rotor assembly and are connected to the paired rotor shaft segments one by one. A cooling medium flow channel is arranged in the rotor core.

2. The high-speed permanent magnet motor rotor according to claim 1, characterized in that: The rotor core includes a first rotor core and a second rotor core. The first rotor core is sleeved outside the second rotor core, and the first rotor core and the second rotor core are connected.

3. The high-speed permanent magnet motor rotor according to claim 2, characterized in that: The first rotor core comprises a first core body and a pair of core teeth; The paired core teeth are evenly distributed circumferentially on the first core body, the surface-mounted permanent magnets are evenly attached between adjacent core teeth so that polar regions are formed between adjacent core teeth, the core teeth are provided with tooth flow channels that pass through the axial direction of the first rotor core, and the axial end face of the first core body is provided with core air leakage holes that are evenly distributed circumferentially, and the core air leakage holes and the tooth flow channels are staggered circumferentially.

4. The high-speed permanent magnet motor rotor according to claim 3, characterized in that: The second rotor core includes a core joint matched with the core teeth and a second core body; The core joints are evenly arranged at the ends of the second core body and correspond to the core teeth. The core joints are provided with core flow channels connected to the tooth flow channels for the circulation of cooling medium. The first core body and the second core body are interference connected, and the first core body and the second core body are respectively connected to the rotor shaft segments.

5. The high-speed permanent magnet motor rotor according to claim 3, characterized in that: The rotor shaft segments are all provided with shaft segment air leakage holes, and the shaft segment air leakage holes match the iron core air leakage holes so that the rotor iron core is connected with the outside to balance the air pressure.

6. The high-speed permanent magnet motor rotor according to claim 3, characterized in that: The rotor shaft segment is also provided with a shaft segment groove, and the first core body and the second core body are both provided with notches matching the shaft segment groove, and the shaft segment groove is snap-fitted with the notches.

7. The high-speed permanent magnet motor rotor according to claim 3, characterized in that: The paired rotor shaft segments are each provided with shaft segment through holes, which are respectively connected to the tooth flow channel and the core flow channel. The shaft segment through holes connected to the tooth flow channel are used for the inflow of cooling medium, and the shaft segment through holes connected to the core flow channel are used for the outflow of cooling medium.

8. The rotor for a high-speed permanent magnet motor according to any one of claims 1 to 7, characterized in that: The surface-mounted permanent magnets are arranged in sections along the axial direction of the rotor core, and the pole arc coefficient of the surface-mounted permanent magnets is less than 1.

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