A rotor structure with segmented magnetic steel arrangement and a disc motor

Abstract

The present invention discloses a rotor structure and a disc motor with segmented magnetic steel arrangement, comprising: a rotor disk, magnetic steel slots are distributed on the rotor disk, and magnetic steel is embedded in the magnetic steel slots; the magnetic steel comprises: a unit part divided along the radial direction of the rotor disk; a first unit part, spliced ​​between a second unit part and a third unit part, the first unit part closes the magnetic force lines along the axial direction of the motor to form a first magnetic field occurring along the axial direction of the motor; the second unit part closes the magnetic force lines along the radial direction of the motor to form a second magnetic field perpendicular to the splicing surface on the first unit part; the third unit part closes the magnetic force lines along the radial direction of the motor to form a third magnetic field perpendicular to the splicing surface on the first unit part; the magnetic force lines of two adjacent magnetic steels on the rotor disk: the magnetic force lines of the first unit part have opposite closing directions, the magnetic force lines of the second unit part have the same closing directions, and the magnetic force lines of the third unit part have the same closing directions. The magnetic steel segmentation can reduce the eddy current loss of the permanent magnet and reduce the risk of the magnetic steel falling off due to overheating.

Description

Technical Field

[0001] The present invention relates to the technical field of disc motors, and in particular to a rotor structure with segmented magnetic steel arrangement and a disc motor. Background Art

[0002] The permanent magnets of the disc motor rotor are mainly installed by attaching a whole piece of magnetic steel to the rotor back iron. This type of permanent magnet will generate considerable eddy current loss inside when the motor is running at high speed, which will cause the permanent magnet to overheat and demagnetize, or even cause the permanent magnet to fall off. The eddy current loss of this type of permanent magnet is large, and the large-scale use of high-coercivity NdFeB permanent magnets makes the overall manufacturing cost of the motor high.

[0003] The existing permanent magnet segmentation technology simply divides a permanent magnet with the same magnetization direction into several pieces, either equally or unequally. Although it can effectively reduce the eddy current loss of the permanent magnet, this magnetization method has serious magnetic leakage and poor magnetic field enhancement effect.

[0004] At present, the dual-rotor single-stator disc motor has poor heat dissipation effect, which may cause the stator winding to overheat and the winding insulation layer to be damaged. The heat generated by the stator winding overheating is difficult to dissipate. It may also cause the permanent magnets on the rotor to overheat and irreversibly demagnetize, seriously affecting the output performance of the motor. Summary of the invention

[0005] The technical solution of the present invention is: a rotor structure with segmented magnetic steel arrangement and a disc motor, which are used to solve:

[0006] 1. When the permanent magnet of the disc permanent magnet motor rotor is installed with a whole piece of magnetic steel, when the motor runs at high speed, a considerable eddy current loss will be generated inside it, which will cause the permanent magnet temperature to be too high and demagnetization will occur, and even the permanent magnet will fall off.

[0007] 2. The disc-type permanent magnet motor has poor heat dissipation effect. In order to prevent the permanent magnet from demagnetizing, the disc-type motor stator needs to be cooled.

[0008] The present solution involves a rotor structure with a segmented magnetic steel arrangement, comprising: a rotor disk formed by stacking silicon steel sheets, with magnetic steel slots distributed on the rotor disk, and magnetic steel embedded in the magnetic steel slots; the magnetic steel comprises: unit parts divided along the radial direction of the rotor disk, and the unit parts are contacted and connected through splicing surfaces.

[0009] The unit part specifically includes: a first unit part, a second unit part and a third unit part. Among them:

[0010] The first unit part is spliced ​​between the second unit part and the third unit part, and the first unit part closes the magnetic lines of force along the axial direction of the motor to form a first magnetic field generated along the axial direction of the motor, that is, to form a basic magnetic field;

[0011] The second unit part closes the magnetic field lines along the radial direction of the motor to form a second magnetic field that is perpendicular to the upper joint surface of the first unit part, that is, to form an enhanced magnetic field;

[0012] The third unit part closes the magnetic field lines along the radial direction of the motor to form a third magnetic field perpendicular to the upper joint surface of the first unit part, that is, also forms an enhanced magnetic field;

[0013] Depending on the direction of the magnetic lines of force, the enhanced magnetic field will produce a component of magnetic lines of force in the same direction as the basic magnetic field, which can amplify the basic magnetic field.

[0014] For two adjacent magnetic steels on the rotor disk: the closing directions of the magnetic force lines of the first unit part are opposite, the closing directions of the magnetic force lines of the second unit part are the same, and the closing directions of the magnetic force lines of the third unit part are the same.

[0015] Preferably, the magnetic steel has a strip-shaped fan-shaped structure in the transverse cross section, and has a three-section structure in the transverse cross section, namely: the second unit part, the first unit part, and the third unit part are spliced ​​in sequence, and the third unit part is similar in shape to the second unit part and has the same radial length.

[0016] Preferably, the magnetic steel is a permanent magnet, wherein:

[0017] The first unit part is magnetized along the axial direction of the motor to form a first magnetic field;

[0018] The second unit part is magnetized along the radial direction of the motor to form a second magnetic field;

[0019] The third unit portion is magnetized along the radial direction of the motor to form a third magnetic field.

[0020] Based on the above-mentioned segmented magnetic steel structure, according to parametric modeling and simulation, an ordinary disc motor is compared with the disc motor designed in this scheme, and the torque curves of the two motors are obtained. After comparison, it can be found that the torque of the disc motor designed in this scheme is significantly enhanced, that is, the torque of the disc motor using segmented magnetic steel for magnetic field amplification is enhanced, and the torque pulsation is within a reasonable range. The actual measured torque is 5%-18% higher than that of the ordinary disc motor.

[0021] The second unit part, the first unit part and the third unit part are butted together through the joint surface. Specifically, the unit parts are contact-bonded by coating structural adhesive on adjacent joint surfaces.

[0022] Due to the increase in the magnetic field, the density of the magnetic lines of force is denser than that of ordinary magnets, so it is easier to generate heat. For this reason, an air-cooling structure is added, that is, a fan blade area is arranged on the rotor disk. The fan blade area is located on the side of the magnet in the radial direction of the rotor disk, and spiral blades are arranged in the fan blade area at equal distances along the circular axis. When the rotor disk rotates, because of the spiral blades in the fan blade area, according to the fan principle, the spiral blades generate air flow, which can suck the air on the rear side of the rotor disk into the air gap between the stator and the rotor to cool the stator winding and the rotor magnet; at the same time, the air entering the stator and rotor from the outside of the rotor is also taken out, so that a cooling cycle can be formed.

[0023] Specifically, a first blade area and a second blade area may be provided on the rotor disk, and the first blade area and the second blade area are respectively located on both sides of the magnetic steel in the radial direction of the rotor disk.

[0024] The fans on both sides can use spiral blades with the same spiral direction. In this way, the spiral blades push the airflow in a single direction, that is, the air gap between the stator and the rotor takes in air or discharges air at the same time. In this case, the air circulation effect is not outstanding. If the fans on both sides use spiral blades with different spiral directions, one side takes in air while the other side discharges air, then better convection can be formed, and the cooling circulation effect of the airflow is also the best.

[0025] The number of spiral blades in each fan blade area is generally an odd number, which conforms to the fan blade design principle. There is no specific requirement for the spiral angle of the spiral blade, which is determined according to the preparation process and processing difficulty. At present, the general spiral angle of ordinary fans, that is, 90 degrees, is adopted.

[0026] Based on the above structure, a disc motor includes: a stator and rotors on both sides of the stator.

[0027] The rotor comprises a rotor disk, on which magnetic steel grooves are distributed, in which the segmented magnetic steel is embedded, and a rotating shaft is assembled in the shaft hole of the rotor disk by key connection.

[0028] The magnetic steel in the magnetic steel slot includes:

[0029] The first unit part is magnetized along the axial direction of the motor to form a first magnetic field;

[0030] The second unit part is magnetized along the radial direction of the motor to form a second magnetic field;

[0031] The third unit portion is magnetized along the radial direction of the motor to form a third magnetic field.

[0032] A blade area is respectively arranged on both sides of the magnetic steel in the radial direction of the rotor disk, and spiral blades are arranged in the blade area.

[0033] Preferably, the stator comprises a stator disk, a winding is arranged on the stator disk, and an axial hole of the stator disk is assembled with the rotating shaft through a bearing.

[0034] Preferably, the stator disc is an ironless stator structure.

[0035] Specifically, the stator and the rotor are integrated in the housing, and the housing includes end covers on both sides and a rotating housing between the end covers on both sides. The rotating housing includes a left housing and a right housing, and the left housing and the right housing are butt-jointed to form a butt end.

[0036] The stator is fixedly connected to the butt ends of the left shell and the right shell through a stator disk for assembly connection, and the rotating shaft is assembled with the shaft hole on the end cover through a bearing.

[0037] Therefore, this dual-rotor single-stator structural arrangement can form an enhanced structure with bilaterally symmetrical arrangement. At the same time, air cooling is also carried out from both sides, and the air cooling effect is more prominent.

[0038] The advantages of the present invention are:

[0039] 1. The segmentation of permanent magnets can effectively reduce the eddy current loss of permanent magnets and reduce the risk of permanent magnets falling off due to overheating. By optimizing the segmented combination of permanent magnet materials with large intrinsic coercive force and small residual magnetic flux density and permanent magnet materials with small intrinsic coercive force and large residual magnetic flux density, the low-cost NdFeB with large intrinsic coercive force can be used to the minimum while ensuring the anti-demagnetization ability of the motor. While improving the working efficiency of the disc motor, it can also reduce the cost of the segmented magnetic steel structure motor rotor.

[0040] 2. The motor structure of the present invention is a disc structure with a dual-rotor middle stator. The winding on the middle stator is difficult to dissipate heat. The left and right rotor discs are respectively provided with fan-blade-shaped spiral blades. The spiral blades on the left rotor disc draw air in, eventually forming an air-cooled cooling circuit to cool the stator winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0042] Figure 1 A cross-sectional view of a rotor structure with a segmented magnetic steel arrangement;

[0043] Figure 2 It is a cross-sectional view of a dual-rotor single-stator disc motor;

[0044] Figure 3 is a front view of the rotor disk;

[0045] Figure 4 is the front view of the rotating shaft;

[0046] Figure 5This is the first combination diagram of segmented magnetic steel;

[0047] Figure 6 This is the second combination diagram of segmented magnetic steel;

[0048] Figure 7 It is a simulation diagram of magnetic field line distribution of segmented permanent magnet;

[0049] Figure 8 It is the segmented magnetic steel torque curve;

[0050] Among them, 1. the first bolt; 2. the motor end cover; 3. the rotating shaft; 4. the bearing end cover; 5. the screw; 6. the bearing; 7. the limit block; 8. the flat keyway; 9. the left housing; 10. the stator disk; 11. the second bolt; 12. the right housing; 13. the rotor disk; 14. the second unit; 15. the first unit; 16. the third unit; 17. the winding; 18. the spiral blade. DETAILED DESCRIPTION

[0051] Embodiment 1:

[0052] like Figure 1-8 As shown, a dual-rotor single-stator disc motor includes a rotor and a stator, wherein the rotor includes a rotor disc 13, and the stator includes a stator disc 10. The two rotor discs are respectively located on the left and right sides of the stator disc, and the rotor disc 13 is circular. The rotor disc and the stator disc are both mounted on the rotating shaft 3, and the rotating shaft 3 is provided with a flat key slot 8, and the rotor disc 13 is provided with a key slot of the same size. The rotor discs on the left and right sides of the stator disc are connected to the rotating shaft 3 through flat keys. The shaft hole of the stator disc 10 is supported on the rotating shaft 3 by a bearing, and the outer side of the stator disc is fixedly connected to the rotating housing formed by the left housing 9 and the right housing 12 through a second bolt 11.

[0053] The motor end covers 2 located on the left and right sides of the motor are fixed to the motor shaft 3 through bearings 6, the bearing end covers 4 are fixed to the motor end covers 2 of the motor through screws 5, the bearing end covers 4 and the limit blocks 7 are used for axial positioning of the bearings 6, and the rotating housing is connected to the motor end covers 2 through the first bolts 1.

[0054] like Figure 1 As shown, the rotor disks 13 on both sides of the stator of the dual-rotor single-stator disk motor are formed by laminating silicon steel sheets, and the stator disk 10 is a coreless stator structure composed of a winding 17 and epoxy resin.

[0055] The permanent magnet steel slots are formed on the rotor disk by wire cutting or punching, and the permanent magnet steel slots have the same outer size as the permanent magnets.

[0056] like Figure 5 and 6As shown, the permanent magnets of each pole are distributed radially along the motor from the inside to the outside and are divided into the third unit part 16, the first unit part 15, and the second unit part 14. The first unit part 15 is magnetized along the axial direction of the disc motor. The magnetization directions of the third unit part 16 and the second unit part 14 are perpendicular to the radial end face of the first unit part 15, and the magnetization direction points to the first unit part 15. This magnetization method is used to achieve the axial magnetic flux enhancement effect of the first unit part 15. The third unit part 16, the first unit part 15, and the second unit part 14 are bonded together by high-strength structural adhesive. In order to prevent the permanent magnet from loosening in the permanent magnet steel slot, the contact surface between each segment of the permanent magnet and the disc motor rotor disk 13 is also bonded by high-strength structural adhesive.

[0057] like Figure 5 and 6 As shown, of two adjacent permanent magnets on the dual-rotor single-stator disc motor: the third unit portion 16 and the second unit portion 14 have the same magnetization direction, and the first unit portion 15 of the two adjacent permanent magnets have opposite magnetization directions.

[0058] like Figure 5 and 6 As shown, the use of the segmented magnetic steel structure enhances the magnetic induction intensity of the middle magnetic steel corresponding to the effective length of the winding, which is beneficial to improving the motor torque.

[0059] like Figure 7 As shown in the figure, parametric modeling and simulation of segmented magnetic steel are carried out, and two motor torque curves are obtained. After comparison, it can be found that the torque of the motor is significantly enhanced and the torque pulsation is within a reasonable range.

[0060] In the radial direction of the rotor disk, both sides of the magnetic steel slot are provided with blade areas arranged in a rotating shape along the circumferential direction. The blade areas and the magnetic steel slots are distributed concentrically. Spiral blades 18 are evenly distributed in the two blade areas. The spiral blades 18 have a spiral twist angle of a certain angle, which can blow the wind at the rear and surrounding of the fan to the front of the fan.

[0061] According to the fan blade design principle, the number of fan blades is designed to be an odd number, and the spiral angles of the spiral blades 18 in the two blade areas are opposite. When the disc motor rotor rotates, the spiral blades 18 located on the rotor disks 13 on the left and right sides of the stator disk 10 draw the air outside the rotor disk 13 into the inside of the rotor, forming a cooling circuit to force air cooling for the entire stator disk 10 structure.

[0062] Embodiment 2:

[0063] The three sections of permanent magnets in this scheme are distributed in the shape of "1", and each magnetic steel is in the shape of a trapezoid. It adopts a radial segmented structure and is composed of a third unit part 16, a first unit part 15, and a second unit part 14. The third unit part 16 and the second unit part 14 are made of permanent magnetic materials with relatively large intrinsic coercive force and relatively low residual magnetic flux density, and the first unit part 15 is made of permanent magnetic materials with relatively small intrinsic coercive force and relatively high residual magnetic flux density. Among them, the permanent magnetic materials used in the third unit part 16 and the second unit part 14 are the same permanent magnetic materials, and the third unit part and the second unit part have similar shapes and the same radial length. The permanent magnetic materials used in the third unit part 16, the first unit part 15, and the second unit part 14 are neodymium iron boron permanent magnets. The first unit part 14 is magnetized along the axial direction of the disc motor, and the magnetization direction of the third unit part 16 and the second unit part 14 is perpendicular to the radial end face of the first unit part 15.

[0064] like Figure 6 As shown, the arrows in the third unit 16, the first unit 15, and the second unit 14 represent the magnetization direction, and the length of the arrows represents the magnitude of the residual magnetic flux density. This disc motor uses segmented magnetic steel to reduce the eddy current loss of the motor permanent magnet, and the design of the cooling structure on the rotor disk makes the temperature rise of this motor low, which can effectively ensure the good use of the motor winding insulation layer and permanent magnet. This structural motor can be used in many fields, such as pure electric vehicles, hybrid vehicles, rail transportation, intelligent manufacturing, shipbuilding industry and many other fields.

[0065] The embodiments of the present invention are only illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A rotor structure with segmented magnetic steel arrangement, comprising a rotating shaft and a rotor disk mounted on the rotating shaft, wherein magnetic steel is embedded in the rotor disk; characterized in that: The magnetic steel comprises: a plurality of unit parts spliced ​​in the radial direction of the rotor disk to form a segmented structure; The magnetic steel includes a first unit portion spliced ​​between the second unit portion and the third unit portion, wherein the first unit portion is magnetized along the axial direction of the motor to form a basic magnetic field generated along the axial direction of the motor; The second unit part and the third unit part are magnetized along the radial direction of the motor to form an enhanced magnetic field pointing perpendicularly to the direction of the basic magnetic field; The two adjacent magnetic steels on the rotor disk are arranged in such a way that the basic magnetic field directions are opposite, the magnetic force lines of the second unit parts are arranged in the same closing direction, and the magnetic force lines of the third unit parts are arranged in the same closing direction; A blade area is arranged on the rotor disk, and the blade area is located on the side of the magnetic steel in the radial direction of the rotor disk; spiral blades are arranged in the blade area and are evenly distributed along the circular axis.

2. The rotor structure with segmented magnetic steel arrangement according to claim 1, characterized in that: The magnetic steel is a permanent magnet; The first unit part is magnetized along the axial direction of the motor to form the basic magnetic field; The second unit part is magnetized along the radial direction of the motor to form the enhanced magnetic field; The third unit portion is magnetized along the radial direction of the motor to form the enhanced magnetic field.

3. The rotor structure with segmented magnetic steel arrangement according to claim 1, characterized in that: The third unit portion has the same length as the second unit portion.

4. The rotor structure with segmented magnetic steel arrangement according to claim 1, characterized in that: The unit parts are contact-bonded by coating structural adhesive on adjacent joint surfaces.

5. The rotor structure with segmented magnetic steel arrangement according to claim 1, characterized in that: The rotor disk includes a first blade area and a second blade area; the first blade area and the second blade area are respectively located on both sides of the magnetic steel in the radial direction of the rotor disk.

6. The rotor structure with segmented magnetic steel arrangement according to claim 5, characterized in that: The spiral blades in the first blade area and the second blade area have the same / opposite spiral directions.

7. A disc motor having a rotor structure with segmented magnetic steel arrangement according to claim 1, characterized in that: It comprises a stator and a rotor on both sides of the stator; the rotor comprises the rotor disk; a rotating shaft is assembled in the shaft hole of the rotor disk by key connection; the stator comprises a stator disk, and a winding is arranged on the stator disk; the shaft hole of the stator disk is assembled with the rotating shaft by a bearing.

8. The disc motor according to claim 7, characterized in that: The stator disc is a coreless stator structure.

9. The disc motor according to claim 7, characterized in that: The housing comprises end covers on both sides and a rotating housing between the end covers; the stator is fixedly connected to the rotating housing through the stator disk for assembly connection; the rotating shaft is assembled with the shaft hole on the end cover through the bearing.

10. The disc motor according to claim 7, characterized in that: The permanent magnetic material used in the magnetic steel includes but is not limited to neodymium iron boron permanent magnets.

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