A motor rotor, a manufacturing method thereof, and a motor having the same

Abstract

The present invention provides a motor rotor, a manufacturing method thereof, and a motor having the same. The motor rotor includes an outer iron core, a magnet, a plastic encapsulation member, an inner rotor, and a vibration damping member. The outer iron core and the magnet are arranged alternately in the circumferential direction. The plastic encapsulation member is formed by injecting hard glue around the outer iron core and the magnet, and forms an outer rotor together with the outer iron core and the magnet. The plastic encapsulation member has a mounting hole and a first limiting hole, and a first boss is provided on the inner circumferential surface of the mounting hole. The inner rotor is arranged in the mounting hole, and the inner rotor is provided with a second boss and a second limiting hole. An injection space is formed between the inner circumferential surface of the mounting hole, the outer circumferential surface of the inner rotor, the first boss, the second boss, the first limiting hole, the second limiting hole, the end face of the outer rotor, and the end face of the inner rotor. The vibration damping member is formed by injecting soft glue into the injection space, and forms the motor rotor together with the outer rotor and the inner rotor, which ensures the structural strength of the outer rotor while having reliable limiting and vibration damping effects, making the motor rotor move stably, with simple process and high efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and particularly to a motor rotor, a manufacturing method thereof, and a motor having the same. Background Art

[0002] In order to reduce the motor vibration caused by torque ripple during the load of a permanent magnet synchronous motor, thereby improving the noise quality of the motor. Usually, a damping rubber is added between the inner and outer rotor cores to reduce the load vibration, thereby optimizing the motor noise. However, most of the traditional damping rotor structures are applied to the surface-mounted magnetic tile structure. When implementing the damping rotor design, there is sufficient space inside the rotor; for an interior permanent magnet motor, especially a motor with an interior magnet solution in a tangential structure, due to limited space, it is usually necessary to sacrifice the motor performance to produce a damping rotor, which results in material waste and cost increase. Summary of the Invention

[0003] In view of this, the present invention provides a motor rotor, a manufacturing method thereof, and a motor having the same. By injection molding a plastic sealing member and a damping member between the outer iron core and the inner rotor, problems such as complex structure and poor damping effect of the damping member in the prior art are solved.

[0004] The motor rotor provided by the present invention includes:

[0005] An outer iron core and a magnet, which are arranged alternately along the circumference; a radial limiting structure is formed on one side of the magnet close to the axis of the motor rotor, and a limiting groove is formed between the adjacent radial limiting structure and the end face of the outer iron core close to the axis;

[0006] A plastic sealing member, which is formed by injecting hard glue into the space between the front and rear end faces, the inner peripheral surface, and the outer peripheral surface of the outer iron core and the magnet; the plastic sealing member and the outer iron core and the magnet form an integral part, and the integral part serves as an outer rotor; the plastic sealing member has a mounting hole, and a first boss extending inward is formed on the inner peripheral surface of the mounting hole; a first limiting hole along the axial direction is formed on the end face of the plastic sealing member at the limiting groove;

[0007] An inner rotor, which is arranged in the mounting hole. A second boss is formed on the outer peripheral surface of the inner rotor, and a second limiting hole along the axial direction is formed on the end face of the second boss; an injection molding space is formed between the inner peripheral surface of the mounting hole, the outer peripheral surface of the inner rotor, the first boss, the second boss, the first limiting hole, the second limiting hole, the end face of the outer rotor, and the end face of the inner rotor;

[0008] A damping member, which is formed by injecting soft glue into the injection molding space. The outer rotor and the inner rotor are formed into a motor rotor through the injection of the soft glue, which is used to reduce the vibration of the inner rotor and the outer rotor and the stability of the structure.

[0009] Further optionally, the size of the outer iron core is smaller than that of the magnet in the radial direction, and the formed limiting groove is used to position the outer iron core and the magnet in the injection mold.

[0010] Further optionally, the end face of the outer iron core is provided with a positioning hole and a plastic encapsulation hole; the positioning hole is used to position the outer iron core in the injection mold; the plastic encapsulation hole is used to inject and form a plastic rod to strengthen the structural strength of the plastic encapsulation.

[0011] Further optionally, the length of the magnet is greater than that of the outer iron core in the axial direction, so that the plastic encapsulation forms an axial limiting structure for the magnet and the outer iron core on the inner side of the end face.

[0012] Further optionally, the first boss and the second boss are arranged staggeredly.

[0013] Further optionally, the damping member has an end portion and a shaft portion. At least a part of the end portion covers the end face of the outer rotor on the side close to the axis, and at least a part of the end portion covers the end face of the inner rotor on the side far from the axis, which is used to slow down the axial vibration of the outer rotor and the inner rotor and play an axial limiting role.

[0014] Further optionally, a first limiting post connecting the outer rotor and the damping member is formed on the shaft portion in the first limiting hole. The cooperation of the first limiting hole and the first limiting post connects the damping member and the outer rotor into one body, which is used to slow down the tangential vibration of the outer rotor and the tangential force provided by the outer rotor to the damping member, and at the same time play a radial and tangential limiting role on the outer rotor.

[0015] Further optionally, a second limiting post connecting the inner rotor and the damping member is formed on the shaft portion at the second limiting hole. The cooperation of the second limiting hole and the second limiting post connects the damping member and the inner rotor into one body, which is used to slow down the tangential vibration of the inner rotor and the tangential force provided by the damping member to the inner rotor, and at the same time play a radial and tangential limiting role on the inner rotor.

[0016] Further optionally, a labyrinth structure is formed in the space between the inner peripheral surface of the mounting hole, the outer peripheral surface of the inner rotor, the first boss and the second boss on the shaft portion; the outer peripheral surface of the labyrinth structure cooperates with the first boss, and the inner peripheral surface of the labyrinth structure cooperates with the second boss to slow down the tangential vibration between the outer rotor and the inner rotor.

[0017] The present invention also provides a manufacturing method for the motor rotor according to any one of the above, including:

[0018] Arrange the outer iron core and the magnet axially and alternately in an injection mold, align the positioning holes with those of the injection mold, make the outer edge of the outer iron core fit the inner edge of the injection mold, place the positioning key in the positioning hole, and place the limiting key in the limiting groove to fix the outer iron core and the magnet in the injection mold;

[0019] Inject the hard glue into the space between the two end faces, the inner peripheral surface, and the outer peripheral surface of the outer iron core and the magnet to form the plastic-sealed part. Form the axial limiting structure on the two end faces of the plastic-sealed part, and form the first boss on the inner peripheral surface of the installation hole of the plastic-sealed part;

[0020] Embed the inner rotor into the installation hole so that the first boss and the second boss are staggered; form an injection space between the inner peripheral surface of the installation hole, the outer peripheral surface of the inner rotor, the first boss, the second boss, the first limiting hole, the second limiting hole, the outer rotor end face, and the inner rotor end face;

[0021] Inject the soft glue into the injection space to form the damping part; at least a part of the end of the damping part covers the end face of the outer rotor, and at least a part covers the end face of the inner rotor; the shaft part of the damping part is formed with a first limiting column, a second limiting column, and a labyrinth structure.

[0022] The present invention also provides a motor having the motor rotor described in any one of the above or adopting the manufacturing method of the motor rotor described in any one of the above.

[0023] In the present invention, hard glue is injected at both ends, the outer peripheral surface, and the inner peripheral surface of the outer iron core and the magnet to form a plastic-sealed part, which connects the outer iron core and the magnet into one body; axial limiting structures are formed on the two end faces of the plastic-sealed part to axially limit the outer iron core and the magnet, and radial limiting structures are formed on its outer peripheral surface and inner peripheral surface to radially limit the outer iron core and the magnet; soft glue injection holes are formed on the end faces of the plastic-sealed part and the inner rotor, and soft glue is injected between the outer rotor, the inner rotor, and the soft glue injection holes to form a damping part, which injects the outer rotor and the inner rotor into one body, making the motor rotor structure stable and reliable; the end of the damping part covers the end faces of the outer rotor and the inner rotor, reducing axial vibration and playing an axial limiting role, and the shaft part of the damping part is formed with a damping structure to damp radial and tangential vibrations and play a radial and tangential limiting role; the plastic-sealed part and the damping part are injection-molded with materials of different strengths, ensuring the structural strength of the outer rotor while the damping part has reliable limiting and damping effects, making the motor rotor move stably, with simple process and high efficiency. Description of the Drawings

[0024] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0025] The structures, ratios, sizes, etc. illustrated in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.

[0026] Figure 1a It is a schematic diagram of the overall structure of an embodiment of the motor rotor provided by the present invention;

[0027] Figure 1b It is an exploded structure schematic diagram of an embodiment of the motor rotor provided by the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of an embodiment in which the outer iron core and the magnet of the present invention are assembled together;

[0029] Figure 3 It is a schematic diagram of the structure of an embodiment of the outer rotor provided by the present invention;

[0030] Figure 4 It is a schematic diagram of the structure of an embodiment of the inner rotor provided by the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of an embodiment of the damping member provided by the present invention;

[0032] In the figure:

[0033] 1 - outer rotor; 11 - outer iron core; 111 - positioning hole; 112 - plastic sealing hole; 113 - magnet limiting structure; 12 - magnet; 121 - radial limiting structure; 13 - limiting groove; 14 - plastic sealing member; 141 - first limiting hole; 142 - mounting hole; 143 - first boss; 144 - inner peripheral surface of the mounting hole;

[0034] 2 - inner rotor; 21 - second boss; 211 - second limiting hole; 22 - outer peripheral surface of the inner rotor;

[0035] 3 - damping member; 31 - end portion; 32 - shaft portion; 321 - first limiting post; 322 - second limiting post; 323 - labyrinth structure. Detailed implementation manners

[0036] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two, but does not exclude the case of including at least one.

[0038] It should be understood that the term "and / or" used herein is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0039] It should also be noted that the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such commodity or system. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of another identical element in the commodity or system including the said element.

[0040] In the present invention, hard glue is injection-molded at both ends, the outer peripheral surface and the inner peripheral surface of the outer iron core and the magnet to form a plastic sealing member, and the plastic sealing member connects the outer iron core and the magnet into one body; axial limiting structures are formed on both end faces of the plastic sealing member to axially limit the outer iron core and the magnet, and radial limiting structures are formed on its outer peripheral surface and inner peripheral surface to radially limit the outer iron core and the magnet; soft glue injection holes are formed on the end faces of the plastic sealing member and the inner rotor, and soft glue is injection-molded between the outer rotor, the inner rotor and the soft glue injection holes to form a damping member, and the damping member injection-molds the outer rotor and the inner rotor into one body, making the motor rotor structure stable and reliable; the end part of the damping member covers the end faces of the outer rotor and the inner rotor to slow down axial vibration and play an axial limiting role, and a damping structure is formed on the shaft part of the damping member to damp radial and tangential vibrations and play a radial and tangential limiting role; the plastic sealing member and the damping member are injection-molded with materials of different strengths, which ensures the structural strength of the outer rotor while the damping member has reliable limiting and damping effects, making the motor rotor move stably, with simple process and high efficiency.

[0041] Embodiment

[0042] <Overall structure>

[0043] As Figure 1a and 1b As shown, the motor rotor provided in this embodiment includes an outer iron core 11, a magnet 12, a plastic seal 14, an inner rotor 2, and a vibration damping member 3. The outer iron core 11 and the magnet 12 are arranged alternately in the circumferential direction, specifically in a circular pattern. A radial limiting structure is formed on one side of the magnet 12 close to the axis of the motor rotor, and a limiting groove 13 is formed between the adjacent radial limiting structure and the end face of the outer iron core 11 close to the axis. The plastic seal 14 is formed by injecting hard glue into the space between the end faces, inner circumferential surface, and outer circumferential surface of the outer iron core 11 and the magnet 12. The plastic seal 14 and the outer iron core 11 and the magnet 12 form an integral part, and the integral part serves as the outer rotor 1. The outer rotor 1 has a mounting hole 142 for arranging the inner rotor 2 and the vibration damping member 3, and a first boss 143 extending inward is formed on the inner circumferential surface 144 of the mounting hole. A first limiting hole 141 along the axial direction is formed on the end face of the plastic seal 14 at the limiting groove 13. The inner rotor 2 is arranged in the mounting hole 142, a second boss 21 is provided on the outer circumferential surface 22 of the inner rotor, and a second limiting hole 211 along the axial direction is formed on the end face of the second boss 21. An injection space is formed between the inner circumferential surface 144 of the mounting hole, the outer circumferential surface 22 of the inner rotor, the first boss 143, the second boss 21, the first limiting hole 141, the second limiting hole 211, the end face of the outer rotor 1, and the end face of the inner rotor 2. The vibration damping member 3 is formed by injecting soft glue into the injection space. The outer rotor 1 and the inner rotor 2 are formed into a motor rotor by injecting soft glue, which ensures the overall structural strength of the motor rotor. At the same time, the structure formed by the vibration damping member 3 can reduce the vibration of the inner rotor 2 and the outer rotor 1 and play an axial, radial, and tangential limiting role on the inner rotor 2 and the outer rotor 1.

[0044] Preferably, the above-mentioned hard glue is nylon or PBT.

[0045] Preferably, the strength of the hard glue is greater than that of the soft glue, so that the strength of the plastic seal 14 at least meets the strength of the outer rotor 1; the soft glue has a certain softness, and the strength of the vibration damping member 3 at least meets the vibration damping and limiting effects of the vibration damping member 3 on the inner rotor 2 and the outer rotor 1.

[0046] <Outer rotor>

[0047] As Figure 2 and Figure 3As shown in the figure, the outer iron core 11, magnet 12 and plastic package 14 provided in this embodiment form an outer rotor. Along the radial direction, the size of the outer iron core 11 is smaller than that of the magnet 12. A magnet limiting structure is formed on one side of the outer iron core 11 away from the axis. Adjacent magnet limiting structures form magnet limiting grooves. When the magnets 12 are arranged alternately with the outer iron core 11, the magnets 12 can be clamped in the magnet limiting grooves, playing a radial and tangential limiting role for the magnets 12. A radial limiting structure 121 is formed on one side of the magnet 12 close to the axis. The adjacent radial limiting structures 121 and the end face of the outer iron core 11 close to the axis enclose a limiting groove 13, which is matched with the limiting key in the injection mold for positioning the outer iron core 11 and the magnet 12 in the injection mold. Specifically, the axial interface of the limiting groove 13 is trapezoidal.

[0048] Preferably, the end face of the outer iron core 11 is provided with a positioning hole 111 and a plastic package hole 112. The positioning hole 111 is matched with the positioning key in the injection mold for positioning the outer iron core 11 in the injection mold. The plastic package hole 112 is used for injection molding a plastic rod to enhance the structural strength of the plastic package 14. Specifically, the positioning hole 111 is a rectangular hole. When the positioning key is arranged in the positioning hole 111, the outer iron core 11 is fixed axially, radially and tangentially in the injection mold. The plastic package hole 112 is a cylindrical hole, connecting the two end faces of the plastic package 14, improving the connection stability between the outer iron core 11, the magnet 12 and the plastic package 14 and the strength of the overall structure of the outer rotor 1.

[0049] Preferably, the length of the magnet 12 along the axial direction is greater than that of the outer iron core 11. Then, on one side of the end face, the magnet 12 protrudes a part more than the outer iron core 11, so that when injecting hard plastic, the plastic package 14 forms a structure for axially and radially limiting the magnet 12 and the outer iron core 11 on the inner side of the end face.

[0050] <Vibration damping member>

[0051] As Figure 4 and Figure 5 shown in the figure, the vibration damping member 3 provided in this embodiment is formed in the injection space formed between the inner peripheral surface 144 of the mounting hole, the outer peripheral surface 22 of the inner rotor, the first boss 143, the second boss 21, the first limiting hole 141, the second limiting hole 211, the end face of the outer rotor 1 and the end face of the inner rotor 2. At the end of the vibration damping member 3 formed on the end faces of the outer rotor 1 and the inner rotor 2, a part of the end of the vibration damping member 3 close to the axis covers the end face of the outer rotor 1, playing an axial limiting role for the outer rotor 1 and reducing its axial vibration. A part of the end of the vibration damping member 3 far from the axis covers the end face of the inner rotor 2, playing an axial limiting role for the inner rotor 2 and reducing its axial vibration.

[0052] Preferably, a first limiting post 321 adapted to the first limiting hole 141 is formed in the first limiting hole 141. Specifically, the axial cross-section of the first limiting hole 141 is trapezoidal, and a plurality of them are arranged on the plastic package 14 in a circumferential pattern. The structure of the first limiting post 321 corresponds to that of the first limiting hole 141. After the two are matched, the damping member 3 and the plastic package 14 are connected as a whole, which is used to reduce the tangential vibration of the outer rotor 1 and the outer rotor 1 provides a tangential force to the damping member 3, and at the same time plays a radial and tangential limiting role on the outer rotor 1.

[0053] Preferably, a second limiting post 322 adapted to the second limiting hole 211 is formed in the second limiting hole 211. Specifically, the axial cross-section of the second limiting hole 211 is circular, and a plurality of them are arranged on the inner rotor 2 in a circumferential pattern. The structure of the second limiting post 322 corresponds to that of the second limiting hole 211. After the two are matched, the damping member 3 and the inner rotor 2 are connected as a whole, which is used to reduce the tangential vibration of the inner rotor 2 and the damping member 3 provides a tangential force to the inner rotor 2, and at the same time plays a radial and tangential limiting role on the inner rotor 2.

[0054] Preferably, the first boss 143 and the second boss 21 are arranged alternately, so that a labyrinth structure 323 is formed in the space between the inner peripheral surface 144 of the mounting hole, the outer peripheral surface 22 of the inner rotor, the first boss 143, and the second boss 21; a first groove adapted to the first boss 143 is formed on one side of the outer peripheral surface of the labyrinth structure 323, and the first boss 143 and the first groove are matched to reduce the tangential vibration of the outer rotor 1 and the outer rotor 1 provides a tangential force to the damping member 3; a second groove adapted to the second boss 21 is formed on one side of the inner peripheral surface of the labyrinth structure 323, and the second boss 21 and the second groove are matched to reduce the tangential vibration of the inner rotor 2 and the damping member 3 provides a tangential force to the inner rotor 2.

[0055] Specifically, the damping member 3 is of a squirrel-cage structure. The first limiting posts 321 are arranged on the outer side of the damping member 3 in a circumferential pattern, the second limiting posts 322 are arranged on the inner side of the damping member 3 in a circumferential pattern, and the labyrinth structure 323 is integrally annular and is arranged between the first limiting posts 321 and the second limiting posts 322.

[0056] Preferably, the cooperation between the first limiting post 321 and the first limiting hole 141, the cooperation between the second limiting post 322 and the second limiting hole 211, the cooperation between the outer peripheral surface of the labyrinth structure 323 and the first boss 143, and the cooperation between the inner peripheral surface of the labyrinth structure 323 and the second boss 21 increase the contact surface between the damping member 3 and the outer rotor 1 and the inner rotor 2, and thus have a better damping effect; the first limiting posts 321 and the second limiting posts 322 of the damping member 3 connect the outer rotor 1, the damping member 3, and the inner rotor 2 into a whole, making the motor rotor structure compact and the strength reliable.

[0057] <Manufacturing method>

[0058] This embodiment provides a manufacturing method of the motor rotor described in any one of the above, including:

[0059] The outer iron core 11 and the magnet 12 are arranged axially in an injection mold at intervals. The positioning holes 111 are aligned with the positioning holes of the injection mold, so that the outer edge of the outer iron core 11 fits the inner edge of the injection mold. The positioning key is arranged in the positioning hole 111, and the limiting key is arranged in the limiting groove 13, so that the outer iron core 11 and the magnet 12 are fixed in the injection mold;

[0060] Hard glue is injected into the space between the two end faces, the inner peripheral surface and the outer peripheral surface of the outer iron core 11 and the magnet 12 to form a plastic-sealed part 14. An axial limiting structure is formed on the two end faces of the plastic-sealed part 14, and a first boss 143 is formed at the inner peripheral surface 144 of the mounting hole of the plastic-sealed part 14;

[0061] The inner rotor 2 is embedded into the mounting hole 142, so that the first boss 143 and the second boss 21 are arranged in a staggered manner, so that an injection space is formed between the inner peripheral surface 144 of the mounting hole, the outer peripheral surface 22 of the inner rotor, the first boss 143, the second boss 21, the first limiting hole 141, the second limiting hole 211, the end face of the outer rotor 1 and the end face of the inner rotor 2;

[0062] Soft glue is injected into the injection space to form a damping member 3; a part of the end portion 31 of the damping member 3 covers the end face of the outer rotor 1, and a part covers the end face of the inner rotor 2; the shaft portion 32 of the damping member 3 is formed with a first limiting post 321, a second limiting post 322 and a labyrinth structure 323.

[0063] This embodiment also provides a motor having the motor rotor described in any one of the above or adopting the manufacturing method of the motor rotor described in any one of the above.

[0064] The exemplary embodiments of the present disclosure are specifically illustrated and described above. It should be understood that the present disclosure is not limited to the detailed structures, setting methods or implementation methods described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent settings included within the spirit and scope of the appended claims.

Claims

1. A motor rotor, characterized in that, it includes: An outer iron core and magnets, which are arranged alternately along the circumference; a radial limiting structure is formed on one side of the magnet close to the axis of the motor rotor, and a limiting groove is formed between the adjacent radial limiting structure and the end face of the outer iron core close to the axis; A plastic sealing member, which is formed by injecting hard glue into the space between the front and rear end faces, inner peripheral surface and outer peripheral surface of the outer iron core and the magnet; the plastic sealing member and the outer iron core and magnet form an integral part, and the integral part serves as an outer rotor; the plastic sealing member has a mounting hole, and a first boss extending inward is formed on the inner peripheral surface of the mounting hole; when injecting the plastic sealing member, the limiting groove is used to position the outer iron core and magnet in the injection mold; after the plastic sealing member is formed, a first limiting hole along the axis is formed at the position of the limiting groove on the end face of the plastic sealing member; An inner rotor, which is arranged in the mounting hole, a second boss is formed on the outer peripheral surface of the inner rotor, and a second limiting hole along the axis is formed on the end face of the second boss; an injection space is formed between the inner peripheral surface of the mounting hole, the outer peripheral surface of the inner rotor, the first boss, the second boss, the first limiting hole, the second limiting hole, the end face of the outer rotor and the end face of the inner rotor; A damping member, which is formed by injecting soft glue into the injection space, and the outer rotor and the inner rotor are formed into a motor rotor through the injection of the soft glue; The damping member has a shaft portion, and a first limiting post connecting the outer rotor and the damping member is formed in the first limiting hole of the shaft portion, and the cooperation of the first limiting hole and the first limiting post connects the damping member and the outer rotor into one body.

2. The motor rotor according to claim 1, characterized in that, The size of the outer iron core is smaller than the size of the magnet along the radial direction.

3. The motor rotor according to claim 1, characterized in that, The end face of the outer iron core is provided with a positioning hole and a plastic sealing hole; the positioning hole is used to position the outer iron core in the injection mold; the plastic sealing hole is used to inject and form a plastic rod.

4. The motor rotor according to claim 1, characterized in that, The length of the magnet is greater than the length of the outer iron core along the axial direction, and the plastic sealing member forms an axial limiting structure for the magnet and the outer iron core on the inner side of the end face.

5. The motor rotor according to claim 1, characterized in that, The first boss and the second boss are arranged staggeredly.

6. The motor rotor according to claim 1, characterized in that, The damping member has an end portion, at least a part of the end portion close to the axis covers the end face of the outer rotor, and at least a part of the end portion far from the axis covers the end face of the inner rotor.

7. The motor rotor according to claim 6, characterized in that, A second limiting post connecting the inner rotor and the damping member is formed at the second limiting hole of the shaft portion, and the cooperation of the second limiting hole and the second limiting post connects the damping member and the inner rotor into one body.

8. The motor rotor according to claim 6, characterized in that, The shaft part forms a labyrinth structure in the space between the inner peripheral surface of the mounting hole, the outer peripheral surface of the inner rotor, the first boss and the second boss; the outer peripheral surface of the labyrinth structure cooperates with the first boss, and the inner peripheral surface of the labyrinth structure cooperates with the second boss.

9. A manufacturing method of the motor rotor according to any one of claims 1-8, characterized in that it includes: Arranging the outer iron core and the magnet circumferentially and alternately in an injection mold, aligning the positioning holes of the outer iron core with the positioning holes of the injection mold, making the outer edge of the outer iron core fit the inner edge of the injection mold, arranging a positioning key in the positioning hole of the outer iron core, arranging a limit key in the limit groove, and fixing the outer iron core and the magnet in the injection mold; Injecting the hard glue into the space between the two end faces, the inner peripheral surface and the outer peripheral surface of the outer iron core and the magnet to form the plastic sealing member, forming an axial limit structure for the magnet and the outer iron core on the two end faces of the plastic sealing member, and forming the first boss at the inner peripheral surface of the mounting hole of the plastic sealing member; Inserting the inner rotor into the mounting hole so that the first boss and the second boss are staggered; forming an injection space between the inner peripheral surface of the mounting hole, the outer peripheral surface of the inner rotor, the first boss, the second boss, the first limit hole, the second limit hole, the end face of the outer rotor and the end face of the inner rotor; Injecting the soft glue into the injection space to form the damping member; At least a part of the end of the damping member covers the end face of the outer rotor, and at least a part of the end of the damping member covers the end face of the inner rotor; the shaft part of the damping member is formed with a first limit post, a second limit post and a labyrinth structure.

10. A motor, characterized in that it has the motor rotor according to any one of claims 1-8 or adopts the manufacturing method of the motor rotor according to claim 9.

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