Electric machine rotor and permanent magnet synchronous machine

Abstract

The application provides a motor rotor and a permanent magnet synchronous motor. The motor rotor comprises an outer rotor assembly and an inner rotor core. The outer rotor assembly comprises a mounting hole, and the inner rotor core is mounted in the mounting hole. A first axial limiting part protrudes radially from the inner wall of the mounting hole at the first end of the mounting hole. A second axial limiting part protrudes radially from the inner wall of the mounting hole at the second end of the mounting hole. A circumferential limiting part protrudes radially from the inner wall of the mounting hole between the first axial limiting part and the second axial limiting part. The outer circumferential wall of the inner rotor core is provided with a limiting protrusion. When the limiting protrusion moves to the limiting position of the circumferential limiting part, the two ends of the limiting protrusion are axially limited by the first axial limiting part and the second axial limiting part. The motor rotor according to the application has the advantages of simple structure, material saving and low cost.

Description

Technical Field

[0001] This application relates to the field of motor technology, specifically to a motor rotor and a permanent magnet synchronous motor. Background Technology

[0002] To reduce motor vibration caused by torque pulsation under load and thus improve the motor's noise quality, damping rubber is typically added between the inner and outer rotor cores to reduce load vibration and optimize motor noise. However, traditional damping rotor structures are mostly used in surface-mounted magnet structures. For motors with built-in magnets, due to space constraints, damping rotors are usually manufactured at the expense of motor performance, resulting in material waste and increased costs.

[0003] A tangential damping rotor structure is disclosed in the known technology, which adopts damping structures at both ends of the rotor along the axial direction. It has good feasibility. However, the rotor structure is complex, uses more materials, and has a higher cost. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this application is to provide a motor rotor and a permanent magnet synchronous motor that have a simple structure, save materials, and have a low cost.

[0005] To address the aforementioned problems, this application provides a motor rotor, including an outer rotor assembly and an inner rotor core. The outer rotor assembly includes a mounting hole, and the inner rotor core is installed within the mounting hole. A first axial limiting portion protruding radially from the inner wall of the mounting hole is provided at the first end of the mounting hole, and a second axial limiting portion protruding radially from the inner wall of the mounting hole is provided at the second end of the mounting hole. A circumferential limiting portion protruding radially from the inner wall of the mounting hole is provided between the first axial limiting portion and the second axial limiting portion. A limiting protrusion is provided on the outer circumferential wall of the inner rotor core. When the limiting protrusion moves to the limiting position of the circumferential limiting portion, both ends of the limiting protrusion are axially limited by the first axial limiting portion and the second axial limiting portion.

[0006] Preferably, the axial length of the limiting protrusion is less than or equal to the axial distance between the first axial limiting part and the second axial limiting part.

[0007] Preferably, when the limiting protrusion is located at the limiting position of the circumferential limiting part, the outer rotor assembly and the inner rotor core are integrally molded by injection molding with the first molding compound.

[0008] Preferably, the circumferential limiting portion extends along the axial direction of the outer rotor assembly, and the first axial limiting portion and the second axial limiting portion extend along the circumferential direction of the outer rotor assembly.

[0009] Preferably, the first axial limiting portion and the second axial limiting portion are arranged alternately along the circumference of the outer rotor assembly. The circumferential limiting portion corresponding to the first axial limiting portion extends to the first axial limiting portion and forms a first L-shaped structure with the first axial limiting portion. The circumferential limiting portion corresponding to the second axial limiting portion extends to the second axial limiting portion and forms a second L-shaped structure with the second axial limiting portion.

[0010] Preferably, the extension direction of the short side of the first L-shaped structure relative to the long side is the same as the extension direction of the short side of the second L-shaped structure relative to the long side.

[0011] Preferably, the minimum circumferential opening width between the short side of the first L-shaped structure and the long side of the second L-shaped structure is more than 1 / 2 of the circumferential width of the limiting protrusion of the inner rotor core.

[0012] Preferably, the first axial limiting part and the second axial limiting part are located on both sides of the circumferential limiting part and are connected to the circumferential limiting part to form a Z-shaped structure.

[0013] Preferably, the circumferential opening width between the first axial limiting part and the adjacent circumferential limiting part is greater than the circumferential width of the limiting protrusion, and the circumferential opening width between the second axial limiting part and the adjacent circumferential limiting part is less than the circumferential width of the limiting protrusion.

[0014] Preferably, the outer rotor assembly includes an outer rotor core and a permanent magnet, with the permanent magnet embedded inside the outer rotor core.

[0015] Preferably, the outer rotor core includes multiple core units arranged at intervals along the circumference, with mounting slots formed between adjacent core units, and the permanent magnet is embedded in the mounting slots.

[0016] Preferably, the outer rotor core is provided with an axial through hole.

[0017] Preferably, the outer rotor core and the permanent magnet are integrally molded together by injection molding with a second molding compound.

[0018] Preferably, when the outer rotor assembly and the inner rotor core are integrally molded together by injection molding with a first molding compound, the hardness of the first molding compound is less than that of the second molding compound.

[0019] Preferably, the first molding compound is rubber, and the second molding compound is plastic.

[0020] Preferably, the axial height of the permanent magnet is greater than the axial height of the outer rotor core.

[0021] According to another aspect of this application, a permanent magnet synchronous motor is provided, including a motor rotor, which is the motor rotor described above.

[0022] The motor rotor provided in this application includes an outer rotor assembly and an inner rotor core. The outer rotor assembly includes a mounting hole, and the inner rotor core is installed in the mounting hole. A first axial limiting part is provided at the first end of the mounting hole, protruding radially from the inner wall of the mounting hole. A second axial limiting part is provided at the second end of the mounting hole, protruding radially from the inner wall of the mounting hole. A circumferential limiting part is provided between the first and second axial limiting parts, protruding radially from the inner wall of the mounting hole. A limiting protrusion is provided on the outer circumferential wall of the inner rotor core. When the limiting protrusion moves to the limiting position of the circumferential limiting part, both ends of the limiting protrusion are axially limited by the first and second axial limiting parts. This motor rotor can use the structure of the outer rotor assembly itself to form axial and circumferential limiting for the inner rotor core, preventing the inner rotor core from moving and falling off in the circumferential direction, and also preventing the inner rotor core from falling off in the axial direction. It does not require additional parts or additional axial length of the motor rotor. The structure is simple, consumes less material, is easy to implement, and has a low cost. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of a motor rotor according to an embodiment of this application;

[0024] Figure 2 This is a perspective structural diagram of the outer rotor core of an electric motor rotor according to an embodiment of this application;

[0025] Figure 3 This is a perspective structural view of the outer rotor assembly of a motor rotor according to an embodiment of this application;

[0026] Figure 4 This is a three-dimensional structural diagram of the inner rotor core of an electric motor rotor according to an embodiment of this application;

[0027] Figure 5 This is a perspective view of the assembly structure of the inner rotor core and outer rotor assembly of an electric motor rotor according to an embodiment of this application.

[0028] Figure 6 This is an assembly structure diagram of the inner rotor core and outer rotor assembly of an electric motor rotor according to an embodiment of this application;

[0029] Figure 7 This is a perspective structural diagram of a motor rotor according to an embodiment of this application;

[0030] Figure 8 This is a cross-sectional view of a motor rotor according to an embodiment of this application;

[0031] Figure 9 This is a perspective structural view of the outer rotor assembly of a motor rotor according to an embodiment of this application;

[0032] Figure 10This is a three-dimensional structural diagram of the inner rotor core of an electric motor rotor according to an embodiment of this application;

[0033] Figure 11 This is an assembly structure diagram of the inner rotor core and outer rotor assembly of an electric motor rotor according to an embodiment of this application.

[0034] The reference numerals in the attached figures are as follows:

[0035] 1. Inner rotor core; 2. Outer rotor assembly; 3. Mounting hole; 4. First axial limiting part; 5. Second axial limiting part; 6. Circumferential limiting part; 7. Limiting protrusion; 8. First molding compound; 9. Core unit; 10. Permanent magnet; 11. Mounting groove; 12. Axial through hole; 13. Second molding compound. Detailed Implementation

[0036] See also Figures 1 to 11 As shown, according to an embodiment of this application, the motor rotor includes an outer rotor assembly 2 and an inner rotor core 1. The outer rotor assembly 2 includes a mounting hole 3. The inner rotor core 1 is installed in the mounting hole 3. A first axial limiting part 4 is provided at the first end of the mounting hole 3, which protrudes radially from the inner wall of the mounting hole 3. A second axial limiting part 5 is provided at the second end of the mounting hole 3, which protrudes radially from the inner wall of the mounting hole 3. A circumferential limiting part 6, which protrudes radially from the inner wall of the mounting hole 3, is provided between the first axial limiting part 4 and the second axial limiting part 5. A limiting protrusion 7 is provided on the outer circumferential wall of the inner rotor core 1. When the limiting protrusion 7 moves to the limiting position of the circumferential limiting part 6, both ends of the limiting protrusion 7 are axially limited by the first axial limiting part 4 and the second axial limiting part 5.

[0037] The motor rotor can use the structure of the outer rotor assembly 2 itself to form axial and circumferential limits on the inner rotor core, preventing the inner rotor core 1 from moving and falling off in the circumferential direction, and also preventing the inner rotor core 1 from falling off in the axial direction. No additional parts are needed, nor is it necessary to increase the axial length of the motor rotor. The structure is simple, consumes less material, is easy to implement, and has a low cost.

[0038] When the limiting protrusion 7 is located at the limiting position of the circumferential limiting part 6, the outer rotor assembly 2 and the inner rotor core 1 are integrally molded together by the first molding compound 8. After the outer rotor assembly 2 and the inner rotor core 1 are assembled, there will be a fitting gap between them. The existence of these fitting gaps may cause the inner rotor core 1 to flip relative to the outer rotor assembly 2, thereby causing the inner rotor core 1 to fall out of the outer rotor assembly 2. Therefore, it is necessary to add a limiting structure to prevent the inner rotor core 1 from flipping.

[0039] In this embodiment, after the inner rotor core 1 rotates into position, the outer rotor assembly 2 simultaneously limits the inner rotor core 1 circumferentially and axially through the first axial limiting part 4, the second axial limiting part 5, and the circumferential limiting part 6. Then, the first molding compound 8 can be filled into the gap between the outer rotor assembly 2 and the inner rotor core 1 for injection molding. The first molding compound 8 is, for example, rubber. While limiting the relative position between the inner rotor core 1 and the outer rotor assembly 2, the elastic properties of the rubber can be used to achieve a vibration-damping connection between the outer rotor assembly 2 and the inner rotor core 1, forming a vibration-damping rotor and improving the vibration-damping performance of the motor rotor.

[0040] The axial length of the limiting protrusion 7 is less than or equal to the axial distance between the first axial limiting part 4 and the second axial limiting part 5, so that when the limiting protrusion 7 rotates in the circumferential direction, both ends will not be blocked by the first axial limiting part 4 and the second axial limiting part 5, ensuring that the inner rotor core 1 can be assembled smoothly.

[0041] The circumferential limiting part 6 extends along the axial direction of the outer rotor assembly 2, and the first axial limiting part 4 and the second axial limiting part 5 extend along the circumferential direction of the outer rotor assembly 2. This ensures that the first axial limiting part 4 and the second axial limiting part 5 can form a sufficiently large blocking area on the inner rotor core 1 in the axial direction, and the circumferential limiting part 6 can form a sufficiently large blocking area on the inner rotor core 1 in the circumferential direction. This ensures that the first axial limiting part 4, the second axial limiting part 5 and the circumferential limiting part 6 have sufficient structural strength during the cooperation with the inner rotor core 1, thereby improving the structural stability when the outer rotor assembly 2 and the inner rotor core 1 are cooperated.

[0042] In one embodiment, the first axial limiting portion 4 and the second axial limiting portion 5 are arranged alternately along the circumference of the outer rotor assembly 2. The circumferential limiting portion 6, which is provided along the axial direction corresponding to the first axial limiting portion 4, extends to the first axial limiting portion 4 and forms a first L-shaped structure with the first axial limiting portion 4. The circumferential limiting portion 6, which is provided along the axial direction corresponding to the second axial limiting portion 5, extends to the second axial limiting portion 5 and forms a second L-shaped structure with the second axial limiting portion 5.

[0043] The first L-shaped structure and the second L-shaped structure are arranged alternately along the circumference of the motor rotor. The short side of the first L-shaped structure axially limits the first end of the inner rotor core 1, the short side of the second L-shaped structure axially limits the second end of the inner rotor core 1, and the long sides of the first and second L-shaped structures circumferentially limit the inner rotor core 1, thereby effectively preventing the inner rotor core 1 from falling off. The short side of the first L-shaped structure is the first axial limiting part 4, the short side of the second L-shaped structure is the second axial limiting part 5, and the long sides of both the first and second L-shaped structures are circumferential limiting parts 6.

[0044] In one embodiment, the first axial limiting part 4 and the second axial limiting part 5 are both protrusions extending circumferentially along the outer rotor assembly 2, and the circumferential limiting part 6 is a protrusion extending axially along the outer rotor assembly 2.

[0045] The extension direction of the short side of the first L-shaped structure relative to the long side is the same as that of the short side of the second L-shaped structure relative to the long side. Multiple limiting protrusions 7 are provided on the outer periphery of the inner rotor core 1. The limiting protrusions 7 that cooperate with the first L-shaped structure and the limiting protrusions 7 that cooperate with the second L-shaped structure are different. The limiting protrusions 7 that cooperate with the first L-shaped structure and the limiting protrusions 7 that cooperate with the second L-shaped structure are arranged alternately along the circumferential direction. The first L-shaped structure and the second L-shaped structure appear in pairs to form a double L-shaped limiting structure, thereby realizing the circumferential limiting and the axial limiting at both ends of the inner rotor core 1.

[0046] The minimum circumferential opening width between the short side of the first L-shaped structure and the long side of the second L-shaped structure is more than half the circumferential width of the limiting protrusion 7 of the inner rotor core 1. The width of the slot at the tail of the L-shaped structure is more than half the width of the limiting protrusion 7 of the inner rotor core 1. The depth h1 of the groove between the two axial limiting parts of the L-shaped structure is slightly greater than the height h2 of the inner rotor core, ensuring that the inner rotor core has sufficient space when screwed into the groove of the L-shaped structure, and ensuring that the inner rotor core 1 can be firmly and reliably placed therein.

[0047] The limiting protrusions 7 of the inner rotor core 1, which cooperate with the double L-shaped limiting structure, extend axially to both ends of the inner rotor core 1. The axial height of the limiting protrusions 7 is the same as the axial height of the inner rotor core 1. The inner rotor core 1 is made by stacking the same type of rotor laminations, which can be completed in one process, greatly reducing mold costs and improving production efficiency. The inner rotor core 1 has several bosses along its outer circumference to form the limiting protrusions 7. The shape of the limiting protrusions 7 can be determined as needed, and the number should be consistent with the number of L-shaped structures in the double L-shaped limiting structure of the outer rotor assembly 2. The axial length of the limiting protrusions 7 should be less than the depth of the groove between the two axial limiting parts. The relationship between the circumferential width a of the limiting protrusions 7 and the width b of the two axial limiting parts is: b > a / 2.

[0048] The two L-shaped structures mentioned above, which are opposite and misaligned, can also be replaced by shapes such as "L 7" or "LГ".

[0049] In one embodiment, the first axial limiting portion 4 and the second axial limiting portion 5 are located on both sides of the circumferential limiting portion 6 and are connected to the circumferential limiting portion 6 to form a Z-shaped structure. The cross-sectional shape of the Z-shaped limiting protrusion 7 can be determined as needed, but they need to appear in pairs.

[0050] A Z-shaped structure consists of three solid sections: the axial limiting parts at the top and bottom are in the shape of an "I" to limit the inner rotor core 1 and prevent it from moving vertically and falling off axially. The circumferential limiting part 6 in the middle section is in the shape of a "┃" to prevent the inner rotor core 1 from moving circumferentially and falling off. The circumferential gap width c between the "I" shaped structures of two adjacent Z-shaped structures must be greater than the circumferential width d of the limiting protrusion 7 of the inner rotor core 1 to ensure that the inner rotor core can be inserted into the gap between the two adjacent Z-shaped structures.

[0051] The circumferential opening width between the first axial limiting part 4 and the adjacent circumferential limiting part 6 is greater than the circumferential width of the limiting protrusion 7, and the circumferential opening width between the second axial limiting part 5 and the adjacent circumferential limiting part 6 is less than the circumferential width of the limiting protrusion 7.

[0052] The inner rotor core, which mates with the Z-shaped outer rotor assembly 2, is formed by stacking two types of rotor laminations. The inner rotor core 1 has several limiting protrusions 7 along its outer circumference. The shape of the limiting protrusions 7 can be determined as needed, and their number must match the number of L-shaped structures in the double L-shaped limiting structure of the outer rotor assembly 2. The axial length of the limiting protrusions 7 must be less than the axial depth of the "┃"-shaped groove in the Z-shaped structure of the outer rotor assembly 2, ensuring sufficient space for the inner rotor core 1 to be screwed into the Z-shaped groove. After the inner rotor core 1 is inserted into the gap between two adjacent Z-shaped structures and rotated, it forms... Figure 11 In the assembly structure shown, the limiting protrusion 7 of the inner rotor core 1 is located between the "I"-shaped protrusions of two adjacent Z-shaped structures to prevent the inner rotor core 1 from moving axially and falling off.

[0053] The outer rotor assembly 2 includes an outer rotor core and a permanent magnet 10, with the permanent magnet 10 embedded inside the outer rotor core.

[0054] The outer rotor core comprises multiple core units 9 arranged circumferentially, with mounting slots 11 formed between adjacent core units 9. Permanent magnets 10 are embedded within the mounting slots 11. The magnetic steel slots at the inner and outer circumferences of the outer rotor core employ a scheme where all magnetic isolation bridges are disconnected. Compared to the traditional scheme where all magnetic isolation bridges of an internally mounted rotor are connected, or where the inner magnetic isolation bridge is connected and the outer magnetic isolation bridge is disconnected, the motor performance is significantly improved.

[0055] The outer rotor core is formed by stacking the same type of rotor laminations, requiring only one stamping process, which greatly reduces mold costs and improves production efficiency. The outer rotor core is provided with axial through holes 12. Some of these axial through holes 12 are used as positioning holes for injection molding of encapsulant to strengthen the structure, while others are used as magnetizing positioning holes to solve the problem of poor magnetization. The axial through holes 12 are preferably circular holes. In this embodiment, the axial through holes 12 used as positioning holes and the axial through holes 12 used as magnetizing positioning holes are arranged alternately along the circumference of the outer rotor core.

[0056] The outer rotor core and the permanent magnet 10 are injection molded together by the second molding compound 13, which can easily form an integrated first axial limiting part 4, second axial limiting part 5 and circumferential limiting part 6. The structure is simple, easy to form, has good structural strength and high forming efficiency.

[0057] When the outer rotor assembly 2 and the inner rotor core 1 are injection molded together by the first molding compound 8, the hardness of the first molding compound 8 is less than that of the second molding compound 13. The lower hardness of the first molding compound 8 can be used to increase the damping when the outer rotor assembly 2 and the inner rotor core 1 move relative to each other, thereby achieving a good shock absorption effect.

[0058] In one embodiment, the first molding compound 8 is rubber, and the second molding compound 13 is plastic.

[0059] In one embodiment, the axial height of the permanent magnet 10 is greater than the axial height of the outer rotor core, which can make full use of the end effect of the permanent magnet 10 and enable the motor to obtain greater output torque.

[0060] The assembly process of the motor rotor in this embodiment of the application is as follows:

[0061] Step 1: Design inner and outer rotor cores with appropriate stacking thicknesses according to development requirements;

[0062] Step 2: Assemble the outer rotor core and permanent magnet 10 together and place them into the injection mold. First, inject the second molding compound to encapsulate the permanent magnet 10 and the outer rotor core to form the outer rotor assembly 2. The inner circumference of the outer rotor assembly 2 forms a double L-shaped or ZZ-shaped limiting structure.

[0063] Step 3: Screw the limiting protrusion 7 of the inner rotor core 1 into the double L-shaped or ZZ-shaped limiting structure;

[0064] Step 4: Inject damping materials such as rubber into the gap between the inner rotor core 1 and the outer rotor assembly 2 to form a damping rotor;

[0065] Step 5: Press the shaft into the vibration-damping rotor and magnetize it through the magnetization positioning hole.

[0066] According to an embodiment of this application, the permanent magnet synchronous motor includes a motor rotor, which is the motor rotor described above.

[0067] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0068] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A motor rotor, characterized in that, The device includes an outer rotor assembly (2) and an inner rotor core (1). The outer rotor assembly (2) includes a mounting hole (3). The inner rotor core (1) is installed in the mounting hole (3). The first end of the mounting hole (3) is provided with a first axial limiting part (4) that protrudes radially from the inner wall of the mounting hole (3). The second end of the mounting hole (3) is provided with a second axial limiting part (5) that protrudes radially from the inner wall of the mounting hole (3). Between the first axial limiting part (4) and the second axial limiting part (5), a circumferential limiting part (6) that protrudes radially from the inner wall of the mounting hole (3) is provided. The outer circumferential wall of the inner rotor core (1) is provided with a limiting protrusion (7). When the limiting protrusion (7) moves to the limiting position of the circumferential limiting part (6), the two ends of the limiting protrusion (7) are axially limited by the first axial limiting part (4) and the second axial limiting part (5). When the limiting protrusion (7) is located at the limiting position of the circumferential limiting part (6), the outer rotor assembly (2) and the inner rotor core (1) are injection molded together by the first molding compound (8); The outer rotor assembly (2) includes an outer rotor core and a permanent magnet (10). The permanent magnet (10) is embedded in the outer rotor core. The outer rotor core and the permanent magnet (10) are injection molded together by a second molding compound (13). The hardness of the first molding compound (8) is less than that of the second molding compound (13).

2. The motor rotor according to claim 1, characterized in that, The axial length of the limiting protrusion (7) is less than or equal to the axial distance between the first axial limiting part (4) and the second axial limiting part (5).

3. The motor rotor according to claim 1, characterized in that, The circumferential limiting portion (6) extends along the axial direction of the outer rotor assembly (2), and the first axial limiting portion (4) and the second axial limiting portion (5) extend along the circumferential direction of the outer rotor assembly (2).

4. The motor rotor according to claim 3, characterized in that, The first axial limiting part (4) and the second axial limiting part (5) are arranged alternately along the circumference of the outer rotor assembly (2). The circumferential limiting part (6) provided along the axial direction corresponding to the first axial limiting part (4) extends to the first axial limiting part (4) and forms a first L-shaped structure with the first axial limiting part (4). The circumferential limiting part (6) provided along the axial direction corresponding to the second axial limiting part (5) extends to the second axial limiting part (5) and forms a second L-shaped structure with the second axial limiting part (5).

5. The motor rotor according to claim 4, characterized in that, The extension direction of the short side of the first L-shaped structure relative to the long side is the same as the extension direction of the short side of the second L-shaped structure relative to the long side.

6. The motor rotor according to claim 4, characterized in that, The minimum circumferential opening width between the short side of the first L-shaped structure and the long side of the second L-shaped structure is more than 1 / 2 of the circumferential width of the limiting protrusion (7) of the inner rotor core (1).

7. The motor rotor according to claim 1, characterized in that, The first axial limiting part (4) and the second axial limiting part (5) are located on both sides of the circumferential limiting part (6) and are connected to the circumferential limiting part (6) to form a Z-shaped structure.

8. The motor rotor according to claim 7, characterized in that, The circumferential opening width between the first axial limiting part (4) and the adjacent circumferential limiting part (6) is greater than the circumferential width of the limiting protrusion (7), and the circumferential opening width between the second axial limiting part (5) and the adjacent circumferential limiting part (6) is less than the circumferential width of the limiting protrusion (7).

9. The motor rotor according to claim 1, characterized in that, The first axial limiting part (4), the second axial limiting part (5) and the circumferential limiting part (6) are integrated.

10. The motor rotor according to claim 1, characterized in that, The outer rotor core includes multiple core units (9) arranged circumferentially, and an mounting groove (11) is formed between adjacent core units (9). The permanent magnet (10) is embedded in the mounting groove (11).

11. The motor rotor according to claim 1, characterized in that, The outer rotor core is provided with an axial through hole (12).

12. The motor rotor according to claim 1, characterized in that, The first molding compound (8) is rubber, and the second molding compound (13) is plastic.

13. The motor rotor according to claim 1, characterized in that, The axial height of the permanent magnet (10) is greater than the axial height of the outer rotor core.

14. A permanent magnet synchronous motor, comprising a motor rotor, characterized in that, The motor rotor is the motor rotor according to any one of claims 1 to 13.

Images