Motor

Abstract

The motor comprises a rotor assembly, the rotor assembly comprises a rotating shaft, a rotor core body and end rings, the rotating shaft penetrates through the rotor core body, the end rings are arranged at the two ends of the rotor core body along the axial direction of the rotating shaft, a cavity is formed in the rotating shaft, the rotating shaft is provided with heat dissipation holes, and the heat dissipation holes are communicated with the cavity; the heat dissipation piece comprises a plurality of blades, and the heat dissipation holes, the cavity and the blades form a heat dissipation channel. The heat dissipation pieces are arranged at the two ends of the rotor core body in a sleeving mode so that stable connection between the heat dissipation pieces and the rotor core body can be kept, and meanwhile heat dissipation can be conducted on the end rings and the rotor core body through the heat dissipation channels formed by the heat dissipation holes, the cavities and the multiple blades; the overall structure of the heat dissipation piece is simple, and the length of the rotor assembly in the axial direction of the rotating shaft is in a controllable range, so that the production cost of the motor is controlled.

Description

[Technical field]

[0001] The utility model relates to the technical field of motors, in particular to a motor. [Background technology]

[0002] As an electromagnetic device for realizing electric energy conversion or transmission, the motor has been widely used in various fields of the industrial industry. During the application process, it was found that the motor's rotor will generate a lot of heat during rotation. If the heat is not dissipated in time, it will affect the operation of the motor.

[0003] Based on the above problems, the related technology proposes a solution of adding a fan and a wind shield at the end of the motor to cool the rotor, but this will increase the axial length of the motor, which is not conducive to the overall axial dimension control and will also increase production costs. [Contents of the utility model]

[0004] The main purpose of the utility model is to provide a motor, which aims to maintain a stable connection between the heat sink and the rotor core by arranging a heat sink, and at the same time, the heat dissipation channel formed by the heat dissipation holes, the cavity and the plurality of blades can dissipate heat for the end ring and the rotor core; the overall structure of the heat sink is simple, and the length of the rotor assembly in the axial direction of the shaft is within a controllable range, so as to control the production cost of the motor.

[0005] To achieve the above-mentioned purpose, the utility model provides a motor, the motor includes a rotor assembly, the rotor assembly includes a rotating shaft, a rotor core and an end ring, the rotating shaft is passed through the rotor core, the end ring is arranged at both ends of the rotor core along the axial direction of the rotating shaft, a cavity is formed in the rotating shaft, the rotating shaft is provided with a heat dissipation hole, and the heat dissipation hole is connected to the cavity;

[0006] The rotor assembly further includes a heat sink, which is sleeved on both ends of the rotor core along the axial direction and includes a plurality of blades. The heat dissipation holes, the cavity and the plurality of blades form a heat dissipation channel.

[0007] In one embodiment of the utility model, the heat sink includes a first mounting portion and a second mounting portion, the first mounting portion is sleeved on the end ring, and the second mounting portion is sleeved on the outer circumference of the rotating shaft;

[0008] Two ends of the plurality of blades are respectively connected to the first mounting portion and the second mounting portion, and the blades are spaced apart around the circumference of the rotor core.

[0009] In one embodiment of the utility model, the rotating shaft is provided with a plurality of first heat dissipation holes and a plurality of second heat dissipation holes at both ends along its axial direction, respectively. The plurality of first heat dissipation holes are arranged at intervals along the circumference of the rotating shaft, and the plurality of second heat dissipation holes are arranged at intervals along the circumference of the rotating shaft.

[0010] In an embodiment of the present invention, the second mounting portion is provided with a hollow portion, and the first heat dissipation hole and / or the second heat dissipation hole are located in the hollow portion.

[0011] In one embodiment of the utility model, the blade includes a first fin and a second fin, a plurality of the first fins are connected to the first mounting portion, a first gap is formed between two adjacent first fins, the first mounting portion is provided with a plurality of vents at intervals around the circumference of the rotating shaft, and the plurality of the first gaps and the plurality of the vents form a first heat dissipation channel;

[0012] A plurality of the second fins are all connected to the second mounting portion, a second gap is formed between two adjacent second fins, and a plurality of the second gaps, the heat dissipation holes and the cavity form the second heat dissipation channel.

[0013] In an embodiment of the present invention, the distance between the first fin and the rotor core along the axial direction of the rotating shaft is greater than the distance between the second fin and the rotor core along the axial direction of the rotating shaft.

[0014] In one embodiment of the utility model, the heat sink further includes a partition portion, a plurality of the first fins connect the first mounting portion and the partition portion, and the second fins connect the partition portion and the second mounting portion;

[0015] The partition portion abuts against a surface of the end ring away from the first mounting portion.

[0016] In one embodiment of the utility model, the heat sink further comprises a plurality of position-limiting undercuts, the plurality of position-limiting undercuts are arranged on the second mounting portion and are arranged at circumferential intervals around the rotating shaft, and the plurality of position-limiting undercuts can be detachably connected to the rotating shaft.

[0017] In one embodiment of the utility model, the rotor core comprises a first core and a second core, the second core is arranged at both ends of the first core along the axial direction of the rotating shaft and forms a mounting groove, the end ring is arranged on the second core; the first mounting portion is sleeved on the outer periphery of the second core;

[0018] The outer diameter of the first core is greater than the outer diameter of the second core, the outer diameter of the end ring is the same as the outer diameter of the second core, and the outer diameter of the first mounting portion is the same as the outer diameter of the first core.

[0019] In an embodiment of the present invention, the end ring is made of cast aluminum alloy.

[0020] After adopting the above technical scheme, the beneficial effects are as follows: the utility model is provided with a heat sink, the heat sink includes a plurality of blades, the rotating shaft is provided with heat dissipation holes, the heat dissipation holes are connected to the internal cavity of the rotating shaft, so that heat exchange can be performed on the rotating shaft and the end rings to reduce the temperature at the rotating shaft and the end rings; at the same time, because the heat sink is sleeved on both ends of the rotor core along the axial direction of the rotating shaft, it plays a limiting role on the end rings, which can make the connection between the end rings and the rotor core more stable; the heat sink is directly sleeved on both ends of the rotor core as an integral structure, so that the axial length of the rotor core in the rotating shaft is within a controllable range, and there is no need to change the size of other components in the motor, thereby reducing production costs.

Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 An overall structural diagram of a heat sink provided by an embodiment of the utility model;

[0023] Figure 2 Another overall structural diagram of the heat sink provided by the embodiment of the utility model from another angle;

[0024] Figure 3 The overall structure diagram of the rotor assembly provided by the embodiment of the utility model;

[0025] Figure 4 A cross-sectional view of a rotor assembly provided in an embodiment of the utility model;

[0026] Figure 5 A three-dimensional cross-sectional view of a rotor assembly provided in an embodiment of the utility model;

[0027] Figure 6 A partial enlarged view of the rotor assembly provided in an embodiment of the utility model.

[0028] Description of Figure Numbers:

[0029] Label name Label name 100 Rotor assembly 10 Rotor core 11 The first core 13 The second core 15 Mounting slot 30 Shaft 31 Cavity 33 First heat dissipation hole 35 Second heat dissipation hole 50 End ring 70 Heat sink 71 First installation part 711 Ventilation holes 73 Second installation part 731 Hollow part 733 Limit undercut 75 First fin 751 First gap 77 Second fin 771 Second gap 79 Divider 200 First heat dissipation channel 300 Second heat dissipation channel [Specific implementation method]

[0030] In order to better understand the technical solution of the utility model, the embodiments of the utility model are described in detail below in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] 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", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0032] It should be understood that the term "and / or" used in this article 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 at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0033] The utility model provides a motor, which includes a stator assembly and a rotor assembly 100. The stator assembly is installed on a casing, a coil is wound around the stator core, and the rotor assembly 100 is fixed on a base through a bearing or a sleeve. The stator assembly and the rotor assembly 100 are not directly connected, but are separated by an air gap, so that the rotor assembly 100 can rotate freely inside the stator assembly.

[0034] The motor of the utility model includes a rotor assembly 100, which includes a rotating shaft 30, a rotor core 10 and an end ring 50. The rotating shaft 30 is penetrated by the rotor core 10, and the end ring 50 is arranged at both ends of the rotor core 10 along the axial direction of the rotating shaft 30. A cavity 31 is formed in the rotating shaft 30, and the rotating shaft 30 is provided with heat dissipation holes, which are connected to the cavity 31; the rotor assembly 100 also includes a heat sink 70, which is sleeved on both ends of the rotor core 10 along the axial direction, and the heat sink 70 includes a plurality of blades, and the heat dissipation holes, the cavity 31 and the plurality of blades form a heat dissipation channel.

[0035] The motor of the present invention can be an induction motor. The working principle of the induction motor is that a three-phase AC power supply is connected through the terminal blocks on the stator assembly to provide current for the stator winding; when the current passes through the stator winding, a magnetic field is generated in the stator core; this magnetic field rotates with the change of the current to form a rotating magnetic field; the rotor winding can be embedded in the rotor core 10, and when the rotating magnetic field acts on the rotor assembly 100, the rotor winding will cut the magnetic flux lines, thereby generating an induced electromotive force and an induced current in the rotor winding; as the induced current is generated, the current in the rotor winding interacts with the rotating magnetic field to generate electromagnetic force; the electromagnetic force causes the rotor assembly 100 to start rotating, thereby realizing the conversion of electrical energy into mechanical energy.

[0036] Since the rotor assembly 100 rotates at a high speed, it is easy to generate high temperature during the rotation process, and the end plate is easy to deform, break and creep under high temperature. To solve this problem, the relevant technology will adopt the method of setting a fan and a wind cover at the end plate to dissipate heat from the end plate, but this heat dissipation method will increase the overall axial length of the rotor assembly 100, and accordingly, the size of the stator assembly also needs to be adaptively changed, thereby changing the overall volume of the motor, increasing the production cost.

[0037] In view of the above problems, the utility model further provides a heat sink 70, which includes a plurality of blades. The shaft 30 is provided with heat dissipation holes, which are connected to the internal cavity 31 of the shaft 30, so that heat exchange can be performed on both the shaft 30 and the end ring 50 to reduce the temperature at the shaft 30 and the end ring 50; at the same time, because the heat sink 70 is sleeved on both ends of the rotor core 10 along the axial direction of the shaft 30, it plays a limiting role on the end ring 50, which can make the connection between the end ring 50 and the rotor core 10 more stable; the heat sink 70, as an integral structure, is directly sleeved on both ends of the rotor core 10, so that the axial length of the rotor core 10 in the shaft 30 is within a controllable range, and there is no need to change the size of other components in the motor, thereby reducing production costs.

[0038] It can be known that the rotor core is part of the main magnetic circuit of the motor, which is used to embed the rotor winding and construct the magnetic circuit to ensure that the magnetic field can be smoothly transmitted inside the motor. The rotor core is usually made of stacked silicon steel sheets to reduce the core loss generated in the rotating magnetic field. The two sides of the silicon steel sheets are coated with insulating paint to ensure that the sheets are insulated from each other; the shaft 30 is a rotating shaft 30 used to connect the load and output power, which can convert electrical energy into mechanical energy and transfer it to the load for work; the end ring 50 is used to protect the internal components of the motor from the influence of the external environment, such as dust, moisture, corrosion and physical damage, so as to extend the service life of the motor; at the same time, the end ring 50 provides support and fixing for the shaft 30, so that a certain gap is maintained between the stator assembly and the rotor assembly 100 to ensure that they can operate stably.

[0039] Figure 1 An overall structural diagram of a heat sink provided by an embodiment of the utility model; Figure 2 Another overall structural diagram of the heat sink provided by the embodiment of the utility model from another angle; Figure 3 The overall structure diagram of the rotor assembly provided by the embodiment of the utility model; Figure 4 A cross-sectional view of a rotor assembly provided in an embodiment of the utility model; Figure 5 A three-dimensional cross-sectional view of a rotor assembly provided in an embodiment of the utility model; Figure 6 A partial enlarged view of the rotor assembly provided in an embodiment of the utility model.

[0040] Reference Figures 1 to 6 In one embodiment of the utility model, the specific structure of the heat sink 70 is described. The heat sink 70 is divided into a first mounting portion 71 and a second mounting portion 73. The plurality of blades can be connected to the two mounting portions by plugging, bonding or other detachable connection methods. Of course, the first mounting portion 71, the second mounting portion 73 and the plurality of blades can also be an integrally formed structure, which is not limited here. The first mounting portion 71 is sleeved on the end ring 50, and plays a role of supporting and limiting the end ring 50; the second mounting portion 73 is sleeved on the rotating shaft 30, and because it is connected to the first mounting portion 71, it is equivalent to connecting the rotating shaft 30 and the end ring 50, so that the two have a stable connection relationship.

[0041] In this embodiment, the heat sink 70 can be cylindrical, and its shape is adapted to the shape of the end ring 50 and the rotating shaft 30. When the heat sink 70 is installed with the end ring 50 and the rotating shaft 30, the problem of stress concentration at the installation location can be avoided. The material of the heat sink 70 can be polyvinyl chloride, silicone rubber, or other non-magnetic, heat-resistant and flexible polymers, which are not limited here. The above materials have low density and weight, and have little impact on the overall rotor assembly 100.

[0042] A plurality of blades are arranged at circumferential intervals around the rotor core 10. When the rotor assembly 100 rotates at a high speed, the plurality of blades can increase the contact area with the air at both ends of the rotor assembly 100. On the one hand, the air flow around the end ring 50 can be accelerated to reduce the temperature of the end ring 50. On the other hand, the agitated air enters the cavity 31 of the rotating shaft 30 through the heat dissipation holes, thereby reducing the temperature of the rotating shaft 30.

[0043] Reference Figure 1 , Figure 2 , Figure 5 and Figure 6In one embodiment of the utility model, in order to improve the heat dissipation efficiency of the rotating shaft 30, the second mounting portion 73 is provided with a hollow portion 731, and the heat dissipation holes are completely exposed at the hollow portion 731. At this time, the heat exchange efficiency between the heat dissipation holes and the outside world is the highest; of course, in other embodiments of the utility model, the heat dissipation holes can also be partially exposed to the hollow portion 731, or can be provided at the portion where the second mounting portion 73 contacts the outer periphery of the rotating shaft 30. Since there is a gap between the second mounting portion 73 and the rotating shaft 30, the heat dissipation holes provided at the portion where the two contact can also exchange heat with the outside world. The number of heat dissipation holes can be one or more, which is not limited here.

[0044] It can be known that there are two end rings 50, so there are also two heat sinks 70, so that the shaft 30 is provided with first heat dissipation holes 33 and second heat dissipation holes 35 on both sides along its axial direction respectively; in order to further improve the heat dissipation efficiency of the shaft 30, the number of the first heat dissipation holes 33 and the second heat dissipation holes 35 are both multiple, and the multiple first heat dissipation holes 33 are arranged at intervals along the circumference of the shaft 30, and the multiple second heat dissipation holes 35 are arranged at intervals along the circumference of the shaft 30.

[0045] Corresponding to the plurality of first heat dissipation holes 33 and the plurality of second heat dissipation holes 35 , the second mounting portion 73 is also provided with a plurality of hollow portions 731 . The setting positions of each first heat dissipation hole 33 and each second heat dissipation hole 35 may be referred to above and will not be described in detail here.

[0046] Reference Figures 1 to 6 In one embodiment of the utility model, in order to further improve the heat dissipation efficiency of the end ring 50 and the rotating shaft 30, the blades are set as first fins 75 and second fins 77, and the multiple first fins 75 are used to increase the air contact area with the end ring 50, and the multiple second fins 77 are used to increase the air contact area with the rotating shaft 30.

[0047] The plurality of first fins 75 are all connected to the first mounting portion 71, and a first gap 751 is formed between two adjacent first fins 75. The plurality of first gaps 751 allow the hot air generated at the end ring 50 to exchange heat with the outside, thereby cooling the end ring 50 so that it will not deform due to excessive temperature during operation, thereby affecting the working state and efficiency of the rotor assembly 100 and the motor. Furthermore, the first mounting portion 71 is provided with a plurality of vents 711 at intervals in the circumferential direction of the rotating shaft 30, thereby further improving the heat dissipation efficiency of the end ring 50, and the plurality of first gaps 751 and the plurality of vents 711 form a first heat dissipation channel 200.

[0048] Similarly, the plurality of second fins 77 are connected to the second mounting portion 73, a second gap 771 is formed between two adjacent second fins 77, and the plurality of second gaps 771, the heat dissipation holes and the cavity 31 form a second heat dissipation channel 300. The structures and functions of the plurality of second fins 77 and the plurality of second gaps 771 can refer to the plurality of first fins 75 and the plurality of second gaps 771; the plurality of second fins 77 can be arranged at an angle.

[0049] It can be understood that the multiple first fins 75 are for heat dissipation of the end ring 50, and the multiple second fins 77 are for heat dissipation of the rotating shaft 30. Compared with setting a blade to dissipate heat for both the end ring 50 and the rotating shaft 30 at the same time, setting the first fins 75 and the second fins 77 for the end ring 50 and the rotating shaft 30 respectively can further improve the heat dissipation efficiency of the heat sink 70 for both.

[0050] Reference Figures 1 to 6 Furthermore, in one embodiment of the present invention, the distance between the first fin 75 and the rotor core 10 along the axial direction of the rotating shaft 30 is greater than the distance between the second fin 77 and the rotor core 10 along the axial direction of the rotating shaft 30 .

[0051] In this embodiment, the axial direction of the rotating shaft 30 can be understood as the length direction of the rotating shaft 30, which is related to the heat dissipation structure corresponding to the first fin 75 and the second fin 77; because the end ring 50 is farther away from the rotor core 10 in the length direction of the rotating shaft 30, in this direction, the distance between the first fin 75 and the rotor core 10 is greater than the distance between the second fin 77 and the rotor core 10.

[0052] This arrangement is to meet the requirements of the first fin 75 and the second fin 77 to dissipate heat to the end ring 50 and the rotating shaft 30 respectively, and at the same time, it can also prevent the air flow directions at the first fin 75 and the second fin 77 from affecting each other, thereby further improving the heat dissipation efficiency of the heat sink 70 to the end ring 50 and the rotating shaft 30.

[0053] Reference Figures 1 to 6 In one embodiment of the utility model, the heat sink 70 further includes a partition 79, a plurality of first fins 75 connecting the first mounting portion 71 and the partition 79, and a second fin 77 connecting the partition 79 and the second mounting portion 73; the partition 79 abuts against a side of the end ring 50 away from the first mounting portion 71.

[0054] In this embodiment, the partition 79 connects the first fin 75 and the second fin 77 together to provide a stable support for them. This helps to ensure the stability of the entire heat sink 70 during rotation; at the same time, the heat dissipation channel can be divided into a first heat dissipation channel 200 and a second heat dissipation channel 300, so that the two heat dissipation channels can operate independently without interfering with each other, thereby improving the heat dissipation efficiency of the end ring 50 and the rotating shaft 30.

[0055] Of course, the partition 79 and other components of the heat sink 70 may be an integrally formed structure, or may be other detachable connection methods, which are not limited here.

[0056] In the related art, the contact between the end ring 50 and the guide bar, under the action of centrifugal force, the centrifugal force generated by the end ring 50 needs to be borne by the contact part, so that the problem of stress concentration will occur at the contact part between the two. By sleeve-arranging the heat sink 70 on the outer periphery of the end ring 50, when the rotor assembly 100 rotates, a part of the centrifugal force generated by the end ring 50 can be distributed to the heat sink 70, thereby reducing the force on the contact part between the guide bar and the end ring 50, so as to reduce stress concentration.

[0057] By setting the partition portion 79 to abut against the side of the end ring 50 away from the first mounting portion 71, the end ring 50 is limited in cooperation with the first mounting portion 71, thereby preventing the end ring 50 from having a tendency to move radially toward the rotor core 10, so as to maintain the connection stability between the end ring 50 and the rotor core 10.

[0058] In order to further improve the connection stability between the end ring 50 and the rotor core 10, the heat sink 70 is also provided with a limit buckle 733. Multiple limit buckles 733 are arranged on the second mounting portion 73 and are arranged at circumferential intervals around the rotating shaft 30. Multiple limit buckles 733 can be detachably connected to the rotating shaft 30.

[0059] Limiting grooves can be correspondingly provided on the outer periphery of the rotating shaft 30 to engage with the limiting undercuts 733, thereby enhancing the connection stability between the second mounting portion 73 and the rotating shaft 30; because the inner and outer sides of the end plate are supported and limited by the first mounting portion 71 and the partition portion 79, and are finally connected to the rotating shaft 30 through the second fin 77, the connection stability between the end ring 50 and the rotor core 10 is further enhanced.

[0060] Reference Figures 4 to 6 In one embodiment of the utility model, the rotor core 10 includes a first core 11 and a second core 13. The second core 13 is arranged at both ends of the first core 11 along the axial direction of the rotating shaft 30 and forms a mounting groove 15. The end ring 50 is arranged on the second core 13; the first mounting portion 71 is sleeved on the outer periphery of the second core 13; the outer diameter of the first core 11 is greater than the outer diameter of the second core 13, the outer diameter of the end ring 50 is the same as the outer diameter of the second core 13, and the outer diameter of the first mounting portion 71 is the same as the outer diameter of the first core 11.

[0061] In this embodiment, the mounting groove 15 is used for the installation of the first mounting portion 71, and the first mounting portion 71 abuts against the groove wall of the mounting groove 15. This connection method can ensure a stable connection between the heat sink 70 and the rotor core 10, reducing looseness or displacement caused by vibration or movement; it also facilitates installation by the user.

[0062] The rotor core 10 includes a first core 11 and a second core 13 . The first core 11 is a main part that provides support for the second core 13 . Meanwhile, the first core 11 and the second core 13 have different diameters, thereby forming the above-mentioned mounting groove 15 for mounting the heat sink 70 .

[0063] The outer diameter of the second core 13 is the same as the outer diameter of the end ring 50, and the outer diameter of the first core 11 is the same as the outer diameter of the first mounting portion 71, so that the rotor assembly 100 as a whole is in the same plane in the radial direction, and its size is within a controllable range in the axial direction, so that the rotor assembly 100 with the heat sink 70 added can also be matched with the original stator assembly without increasing the overall size of the motor, thereby reducing production costs.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A motor, comprising a rotor assembly, the rotor assembly comprising a rotating shaft, a rotor core and an end ring, the rotating shaft passing through the rotor core, the end ring being arranged at both ends of the rotor core along the axial direction of the rotating shaft, a cavity being formed in the rotating shaft, characterized in that: The rotating shaft is provided with a heat dissipation hole, and the heat dissipation hole is connected to the cavity; The rotor assembly further includes a heat sink, which is sleeved on both ends of the rotor core along the axial direction and includes a plurality of blades. The heat dissipation holes, the cavity and the plurality of blades form a heat dissipation channel.

2. The motor according to claim 1, characterized in that The heat sink comprises a first mounting portion and a second mounting portion, wherein the first mounting portion is sleeved on the end ring, and the second mounting portion is sleeved on the outer circumference of the rotating shaft; Two ends of the plurality of blades are respectively connected to the first mounting portion and the second mounting portion, and the blades are spaced apart around the circumference of the rotor core.

3. The motor according to claim 2, characterized in that The shaft is provided with a plurality of first heat dissipation holes and a plurality of second heat dissipation holes at both ends along the axial direction thereof, the plurality of first heat dissipation holes are arranged at intervals along the circumference of the shaft, and the plurality of second heat dissipation holes are arranged at intervals along the circumference of the shaft.

4. The motor according to claim 3, characterized in that The second mounting portion is provided with a hollow portion, and the first heat dissipation hole and / or the second heat dissipation hole are located in the hollow portion.

5. The motor according to claim 3, characterized in that The blade comprises a first fin and a second fin, a plurality of the first fins are connected to the first mounting portion, a first gap is formed between two adjacent first fins, the first mounting portion is provided with a plurality of vents at intervals in the circumferential direction of the rotating shaft, and the plurality of the first gaps and the plurality of the vents form a first heat dissipation channel; A plurality of the second fins are all connected to the second mounting portion, a second gap is formed between two adjacent second fins, and a plurality of the second gaps, the heat dissipation holes and the cavity form a second heat dissipation channel.

6. The motor according to claim 5, characterized in that The distance between the first fin and the rotor core along the axial direction of the rotating shaft is greater than the distance between the second fin and the rotor core along the axial direction of the rotating shaft.

7. The motor according to claim 5, characterized in that The heat sink further includes a partition, a plurality of the first fins connect the first mounting portion and the partition, and the second fins connect the partition and the second mounting portion; The partition portion abuts against a surface of the end ring away from the first mounting portion.

8. The motor according to claim 7, characterized in that The heat sink also includes a plurality of limit buckles, which are arranged on the second mounting portion and are spaced apart around the circumference of the rotating shaft. The plurality of limit buckles can be detachably connected to the rotating shaft.

9. The electric machine according to any one of claims 2 to 8, characterized in that The rotor core comprises a first core and a second core, the second core is arranged at both ends of the first core along the axial direction of the rotating shaft and forms a mounting groove, the end ring is arranged on the second core; the first mounting portion is sleeved on the outer periphery of the second core; The outer diameter of the first core is greater than the outer diameter of the second core, the outer diameter of the end ring is the same as the outer diameter of the second core, and the outer diameter of the first mounting portion is the same as the outer diameter of the first core.

10. The motor according to claim 1, characterized in that The material of the end ring is cast aluminum alloy.

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