Motor rotor and motor

Abstract

The present invention relates to the field of motor technology, and in particular to a motor rotor and a motor including the motor rotor. The motor rotor includes a rotating shaft and a rotor core, the rotating shaft includes a front shaft section, a middle shaft section and a rear shaft section, the two ends of the middle shaft section are respectively insulated and connected with the front shaft section and the rear shaft section, a metal sleeve is fixedly sleeved on the middle shaft section, the two ends of the metal sleeve are respectively insulated and connected with the two ends of the middle shaft section and there is a gap between the front shaft section and the rear shaft section, the rotor core is sleeved on the metal sleeve, the front shaft section and the rear shaft section are respectively provided with a front shaft positioning member and a rear shaft positioning member near the middle shaft section, and the front shaft positioning member and the rear shaft positioning member are respectively insulated and abutted with the two side surfaces of the rotor core. The present invention makes the front shaft section and the rear shaft section not have a common potential with the rotor core, there is no potential difference between the inner ring of the bearing and the motor housing, and the risk of electrical corrosion of the bearing is fundamentally eliminated; at the same time, sleeved on the metal sleeve is also conducive to improving the anti-torque effect between the rotor core and the rotating shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a motor rotor and a motor comprising the motor rotor. Background Art

[0002] For motors driven by inverters, a common-mode voltage will be generated on the rotor core of the motor due to PWM variable frequency speed regulation and other reasons, resulting in a potential difference between the inner ring of the bearing mounted on the rotating shaft and the motor housing. Since the bearing mounted on the rotating shaft is lubricated with insulating grease, a capacitor is formed between the bearing roller and the outer ring of the bearing in contact with the motor housing. The continuous potential difference between the inner ring of the bearing and the motor housing causes the capacitor to gradually accumulate charge until it exceeds the insulation capacity of the bearing oil film. The accumulated charge is then discharged through the bearing oil film, causing electrical corrosion in the bearing and seriously reducing the life of the bearing.

[0003] In order to prevent the bearing from electrocorrosion, the traditional methods are: 1. Add a filter circuit to the inverter to make the input voltage of the motor smoother to eliminate the common mode voltage; 2. Use a multi-level inverter to eliminate the common mode voltage; 3. Set a grounding device on the motor shaft to eliminate the potential difference; 4. Use conductive bearing grease to avoid the formation of capacitance; 5. Use non-conductive bearing balls, such as ceramic balls, to avoid the formation of capacitance. Although the above methods can solve the problem of electrocorrosion of bearings, they also bring new problems, such as a serious increase in the production cost of the motor, a serious reduction in the working efficiency of the motor, and the need for later maintenance and replacement. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a motor rotor which can prevent the bearings in the motor from being electrolytically eroded, so as to overcome the above-mentioned defects of the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a motor rotor, comprising a rotating shaft and a rotor core, wherein the rotating shaft comprises a front shaft section, a middle shaft section and a rear shaft section, wherein two ends of the middle shaft section are respectively insulated and connected with the front shaft section and the rear shaft section, wherein a metal sleeve is sleeved and fixed on the middle shaft section, wherein two ends of the metal sleeve are respectively insulated and connected with two ends of the middle shaft section and are spaced apart from the front shaft section and the rear shaft section, wherein the rotor core is sleeved on the metal sleeve, wherein the front shaft section and the rear shaft section are respectively provided with a front shaft positioning piece and a rear shaft positioning piece at positions close to the middle shaft section, wherein the front shaft positioning piece and the rear shaft positioning piece are respectively insulated and abutted against two side surfaces of the rotor core.

[0007] Preferably, the outer diameters of the two end portions of the metal sleeve are smaller than the outer diameter of the middle portion of the metal sleeve, and the two end portions of the metal sleeve are fixedly connected to the two ends of the central shaft section by winding insulating material.

[0008] Preferably, the inner surfaces of the two end portions of the metal sleeve and the inner surface of the middle portion of the metal sleeve are in contact with the outer surface of the middle shaft segment.

[0009] Preferably, the inner surfaces of the two end portions of the metal sleeve are in contact with the outer surface of the middle shaft section, and a cavity is formed between the inner surface of the middle portion of the metal sleeve and the outer surface of the middle shaft section.

[0010] Preferably, the cross-sectional shape of the outer contour of the metal sleeve is non-circular, and the inner contour of the connecting hole on the rotor core matches the shape of the outer contour of the metal sleeve.

[0011] Preferably, the cross-sectional shape of the middle shaft segment is non-circular, and the inner contour of the mating portion between the metal sleeve and the middle shaft segment matches the outer contour of the middle shaft segment.

[0012] Preferably, one of the front axle locating piece and the rear axle locating piece is an axial shoulder, and the other is a nut. The front axle section or the rear axle section is provided with a threaded section for threadedly cooperating with the nut. The axial shoulder and the nut are respectively insulated and abutted against the two side surfaces of the rotor core.

[0013] Preferably, the front axle positioning member and the rear axle positioning member are nuts, the front axle section and the rear axle section are both provided with threaded sections for threadedly cooperating with the nuts, and the two side surfaces of the rotor core are insulated and abutted against the two nuts respectively.

[0014] Preferably, the rotor core and the front axle positioning member, and the rotor core and the rear axle positioning member are insulated and abutted by gaskets with insulating function.

[0015] The present invention also provides a motor, comprising the motor rotor as described above.

[0016] Compared with the prior art, the present invention has significant improvements:

[0017] After the motor rotor is assembled to the motor housing, bearings are sleeved on the front shaft section and the rear shaft section. The middle shaft section of the present invention is insulated and connected to the front shaft section and the rear shaft section. The two ends of the metal sleeve on the middle shaft section are respectively insulated and connected to the two ends of the middle shaft section and there is a gap between the front shaft section and the rear shaft section respectively. The front shaft positioning member and the rear shaft positioning member are respectively insulated and abutted against the two side surfaces of the rotor core, so that the front shaft section and the rear shaft section are not in common potential with the rotor core, and there is no potential difference between the inner ring of the bearing and the motor housing, that is, the risk of electrical corrosion of the bearing is fundamentally eliminated, and the life of the bearing is guaranteed. Since the present invention is an improvement on the rotor in the motor, it has the effect of preventing the bearings in the motor from electrical corrosion during the entire life cycle of the motor, does not require subsequent maintenance and replacement, and has little impact on the production cost and work efficiency of the motor. At the same time, the rotor core is not directly sleeved on the middle shaft section, but is sleeved on the metal sleeve, which is beneficial to improve the anti-torque effect between the rotor core and the rotating shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the motor rotor in the first embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the first material composition of the rotating shaft in the first embodiment of the present invention.

[0020] Figure 3 It is a schematic diagram of the second material composition of the rotating shaft in the first embodiment of the present invention.

[0021] Figure 4 It is a schematic diagram of the third material composition of the rotating shaft in the first embodiment of the present invention.

[0022] Figure 5 It is a schematic diagram of the fourth material composition of the rotating shaft in the first embodiment of the present invention.

[0023] Figure 6 It is a schematic diagram of the installation of the metal sleeve of the rotating shaft in the first embodiment of the present invention.

[0024] Figure 7 It is a schematic diagram of the cross-sectional shape of the middle shaft section of the rotating shaft in the first embodiment of the present invention.

[0025] Figure 8 It is a schematic diagram of the installation of the motor rotor in the first embodiment of the present invention.

[0026] Fig. 9 It is a schematic structural diagram of the front shaft section of the rotating shaft in the first embodiment of the present invention.

[0027] Fig.10 It is a schematic diagram of the structure of the motor rotor in the second embodiment of the present invention.

[0028] Fig.11 It is a schematic diagram of the installation of the motor rotor in the second embodiment of the present invention.

[0029] Fig.12 It is a schematic diagram of the structure of the motor rotor in the third embodiment of the present invention.

[0030] Fig.13 It is a schematic diagram of the structure of the motor rotor in the fourth embodiment of the present invention.

[0031] The reference numerals are described as follows:

[0032] 1. Rotating shaft 3. Metal sleeve

[0033] 11. Front axle section a, insulation material

[0034] 111. Front axle positioning part b. Metal material

[0035] 112. Columnar structure c. Fiber material

[0036] 12. Middle axis section d, cavity

[0037] 13. Rear axle section e, axial shoulder

[0038] 131. Rear axle positioning piece f, nut

[0039] 2. Rotor core g, gasket DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0041] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] Furthermore, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0044] Embodiment 1

[0045] like Figures 1 to 9 FIG. 1 shows a first embodiment of the motor rotor of the present invention.

[0046] See also Figure 1The motor rotor of the first embodiment includes a rotating shaft 1 and a rotor core 2. The rotating shaft 1 includes a front shaft section 11, a middle shaft section 12 and a rear shaft section 13. The two ends of the middle shaft section 12 are respectively insulated and connected with the front shaft section 11 and the rear shaft section 13. A metal sleeve 3 is sleeved and fixed on the middle shaft section 12. The two ends of the metal sleeve 3 are respectively insulated and connected with the two ends of the middle shaft section 12 and there are gaps between the front shaft section 11 and the rear shaft section 13. The rotor core 2 is sleeved on the metal sleeve 3. The front shaft section 11 and the rear shaft section 13 are respectively provided with a front shaft positioning member 111 and a rear shaft positioning member 131 near the middle shaft section 12. The front shaft positioning member 111 and the rear shaft positioning member 131 are respectively insulated and abutted with the two side surfaces of the rotor core 2. After the motor rotor is assembled to the motor housing, bearings are sleeved on the front shaft section 11 and the rear shaft section 13. The middle shaft section 12 of the first embodiment is insulated and connected to the front shaft section 11 and the rear shaft section 13. The two ends of the metal sleeve 3 on the middle shaft section 12 are respectively insulated and connected to the two ends of the middle shaft section 12 and there are gaps between the front shaft section 11 and the rear shaft section 13. The front shaft positioning member 111 and the rear shaft positioning member 131 are respectively insulated and abutted against the two side surfaces of the rotor core 2, so that the front shaft section 11 and the rear shaft section 13 are not in common potential with the rotor core 2, and the inner ring of the bearing is insulated and abutted against the two side surfaces of the rotor core 2. Therefore, there is no potential difference between the motor housings, which fundamentally eliminates the risk of electrical corrosion of the bearings and ensures the life of the bearings. Since the first embodiment of the present invention is an improvement on the rotor in the motor, it has the effect of preventing electrical corrosion of the bearings in the motor throughout the life cycle of the motor, does not require subsequent maintenance and replacement, and has little impact on the production cost and work efficiency of the motor. At the same time, the rotor core 2 is not directly sleeved on the middle shaft section 12, but is sleeved on the metal sleeve 3, which is beneficial to improve the anti-torque effect between the rotor core 2 and the rotating shaft 1.

[0047] Preferably, see Figure 2 In the first embodiment, the middle shaft section 12 is made of insulating material a. Since the material of the middle shaft section 12 and the material of the rotor core 2 have a very large temperature deformation difference, a metal sleeve 3 is sleeved on the middle shaft section 12. The cooperation between the metal sleeve 3 and the rotor core 2 is also beneficial to protect the middle shaft section 12 and prevent the middle shaft section 12 of the rotating shaft 1 from being damaged when the motor is working in an environment with a large temperature change range. It should be noted that, see Figure 3 and Figure 4 The middle shaft section 12 may also be in the form of insulating material a at both ends and metal material b in the middle, or metal material b and insulating material a are alternately arranged.

[0048] Specifically, in the first embodiment, the insulating material a is an insulating glass fiber composite material. It should be noted that the insulating material a can also be a carbon fiber composite material that is approximately insulating. The glass fiber composite material is a composite of glass fiber and resin, and the carbon fiber composite material is a composite of carbon fiber and resin. The middle shaft section 12 is made of a glass fiber composite material or a carbon fiber composite material, which not only enables the middle shaft section 12 to obtain good insulation properties, but also enables the middle shaft section 12 to obtain sufficient processing accuracy and torsion resistance, thereby extending the service life of the rotating shaft 1.

[0049] Furthermore, in the first embodiment, the middle shaft section 12 is filled with a material for strengthening the mode and strength of the middle shaft section 12. Due to the requirements of the fiber material winding process, the middle shaft section 12 is a hollow structure, which makes the mode and strength of the middle shaft section 12 poor. Filling the middle shaft section 12 with material is conducive to strengthening the mode and strength of the middle shaft section 12. At the same time, for the traditional one-piece hollow shaft, the yield rate of the hollow shaft is low due to the long middle cavity, while the shaft 1 in the first embodiment can be processed in sections, thereby greatly improving the yield rate of the shaft 1, which is conducive to reducing the production cost of the shaft 1.

[0050] Preferably, in the first embodiment, the material of the front shaft section 11 is medium carbon steel or low carbon steel. Since the front shaft section 11 needs to be processed with structures such as splines to cooperate with the peripherals of the motor to provide or receive torque, and since the front shaft section 11 is equipped with a bearing, the front shaft section 11 also needs to be able to resist micro-wear between the bearing inner ring, and the use of medium carbon steel or low carbon steel, which is a common material for traditional motor shafts, is conducive to ensuring the structural strength of the front shaft section 11.

[0051] Preferably, see Figure 3 In the first embodiment, the rear axle section 13 is also made of medium carbon steel or low carbon steel. Since the rear axle section 13 is also equipped with a bearing, the rear axle section 13 needs to be able to resist the micro-motion wear between the bearing and the rear axle section 13. The use of medium carbon steel or low carbon steel is conducive to ensuring the structural strength of the rear axle section 13. It should be noted that when the motor rotor is working in an environment where the rotation speed of the shaft 1 is low and the micro-motion wear between the rear axle section 13 and the bearing is small, see Figure 5 The material of the rear axle section 13 may also be the same as that of the middle axle section 12 . In this case, the middle axle section 12 and the rear axle section 13 are processed as one piece.

[0052] Preferably, see Figure 2The outer diameters of the two end portions of the metal sleeve 3 are smaller than the outer diameter of the middle portion of the metal sleeve 3, and the two end portions of the metal sleeve 3 are fixedly connected to the two ends of the central shaft section 12 by winding the insulating material c. The outer diameters of the two end portions of the metal sleeve 3 are smaller than the outer diameter of the middle portion of the metal sleeve 3, so that the space required for winding the fiber material c can be reserved, ensuring that the outer diameters of the two end portions of the metal sleeve 3 after winding the fiber material c are smaller than or equal to the outer diameter of the middle portion of the metal sleeve 3, so that the rotor core 2 can be smoothly sleeved on the metal sleeve 3.

[0053] Specifically, in the first embodiment, the fiber material c is a glass fiber composite material. It should be noted that the fiber material c may also be a carbon fiber composite material. Figure 6 The steps for installing the metal sleeve 3 on the middle shaft section 12 are: firstly, the middle shaft section 12 is processed by a winding process, and then the metal sleeve is inserted into the middle shaft section 12, and then the glass fiber composite material or the carbon fiber composite material is wound around the two end parts of the metal sleeve 3, and it is ensured that the outer diameters of the two end parts of the wound metal sleeve 3 are less than or equal to the outer diameter of the middle part of the metal sleeve 3. At this point, the metal sleeve 3 is installed on the middle shaft section 12.

[0054] Preferably, see Figure 1 The inner surfaces of the two end portions of the metal sleeve 3 and the inner surface of the middle portion of the metal sleeve 3 are in contact with the outer surface of the middle shaft section 12 .

[0055] Preferably, the cross-sectional shape of the outer contour of the metal sleeve 3 is non-circular, and the inner contour of the connection hole on the rotor core 2 matches the shape of the outer contour of the metal sleeve 3. When the motor peripherals transmit torque to the rotor core 2 or the rotor core 2 transmits torque to the motor peripherals, the middle shaft section 12 can provide a larger anti-rotation torque to ensure the relative fixation between the middle shaft section 12 and the rotor core 2.

[0056] Preferably, in the first embodiment, the cross-sectional shape of the outer contour of the metal sleeve 3 can be any one of an oval shape consisting of a rectangle and two semicircles, a regular pentagon, a square with rounded corners, and an ellipse.

[0057] Preferably, the cross-sectional shape of the middle shaft segment 12 is non-circular, and the inner contour of the mating portion of the metal sleeve 3 and the middle shaft segment 12 matches the outer contour of the middle shaft segment 12 to improve the relative fixing effect of the metal sleeve 3 and the middle shaft segment 12 in the torsional direction.

[0058] Preferably, in the first embodiment, the cross-sectional shape of the middle shaft section 12 can be as follows: Figure 7 a is a round shape consisting of a rectangle and two semicircles, as shown in Figure 7 b shows a regular pentagon, such as Figure 7 c shows a square with rounded corners, such as Figure 7 Any of the ellipses shown in d.

[0059] Preferably, one of the front axle positioning member 111 and the rear axle positioning member 131 is an axial shoulder e, and the other is a nut f. The front axle section 11 or the rear axle section 13 is provided with a threaded section for threadedly matching with the nut f. The axial shoulder e and the nut f are respectively insulated and abutted against two side surfaces of the rotor core 2. In the first embodiment, there are two configuration schemes for the front axle positioning member 111 and the rear axle positioning member 131: the first scheme is that the front axle positioning member 111 is the axial shoulder e, and the rear axle positioning member 131 is the nut f; the second scheme is that the front axle positioning member 111 is the nut f, and the rear axle positioning member 131 is the axial shoulder e.

[0060] Specifically, taking the first scheme as an example, in this embodiment one, the front axle positioning member 111 is an axial shoulder e, the rear axle positioning member 131 is a nut f, and the rear axle segment 13 is provided with a threaded segment for threadedly matching with the nut f. The axial shoulder e on the front axle segment 11 and the nut f on the rear axle segment 13 are respectively insulated and abutted against the two side surfaces of the rotor core 2.

[0061] Preferably, see Figure 1 and Figure 8 The rotor core 2 and the front axle positioning member 111, and the rotor core 2 and the rear axle positioning member 131 are insulated and abutted by a gasket g having an insulating function. It should be noted that, since the gasket g is insulated from the rotor core 2, the shaft segment to which the gasket g is installed can be either a metal front shaft segment 11 or a rear shaft segment 13, or a non-metal middle shaft segment 12.

[0062] Further, see Figure 1 and Figure 8 In the first embodiment, the front axle positioning member 111 is an axial shoulder e, the rear axle positioning member 131 is a nut f, the rear axle segment 13 is provided with a threaded segment for threaded connection with the nut f, and the rotor core 2 and the axial shoulder e, and the rotor core 2 and the nut f are insulated and abutted by a gasket g having an insulating function. Figure 8 The steps for installing the rotor core 2 on the rotating shaft 1 are as follows: first, a gasket g is sleeved on the axial shoulder e position of the front shaft section 11, and then the rotor core 2 is inserted into the metal sleeve 3 of the middle shaft section 12, and then a gasket g is sleeved on the rear shaft section 13. After that, a nut f is screwed into the rear shaft section 13, and the two side surfaces of the rotor core 2 are respectively abutted against the two gaskets g by tightening the nut f. At this point, the rotor core 2 is installed and fixed to the rotating shaft 1.

[0063] Preferably, see Fig. 9In the first embodiment, the contact portion between the front axle segment 11 and the middle axle segment 12 is provided with an axially protruding columnar structure 112, the diameter of the columnar structure 112 is smaller than the diameter of the front axle segment 11, and the middle axle segment 12 is insulatedly connected to the front axle segment 11 by winding a glass fiber composite material or a carbon fiber composite material around the columnar structure 112.

[0064] Specifically, in the first embodiment, the maximum outer diameter of the metal sleeve 3 is less than or equal to the diameter of the front axle section 11 to ensure that the gasket g can be smoothly sleeved on the front axle section 11 .

[0065] Preferably, in the first embodiment, the gasket g is an insulating gasket made of insulating material or a metal gasket with an insulating coating.

[0066] Specifically, in the first embodiment, only one insulating gasket may be used between the rotor core 2 and the axial shoulder e or the nut f, or multiple insulating gaskets may be used, or a metal gasket may be added between the insulating gasket and the rotor core to achieve other purposes such as tolerance correction.

[0067] The first embodiment also provides a motor, comprising the motor rotor as described above.

[0068] Embodiment 2

[0069] like Figure 10 to Figure 11 The second embodiment of the motor rotor of the present invention is shown in FIG. The second embodiment is basically the same as the first embodiment, and the similarities are not repeated here. The difference is that, see Fig.10 In the second embodiment, the front axle positioning member 111 and the rear axle positioning member 131 are both nuts f, and the front axle section 11 and the rear axle section 13 are both provided with threaded sections for threaded connection with the nuts f, and the two side surfaces of the rotor core 2 are insulated and abutted against the two nuts f respectively.

[0070] Specifically, see Fig.10 and Fig.11 In the second embodiment, the front axle positioning member 111 and the rear axle positioning member 131 are both nuts f, and the front axle section 11 and the rear axle section 13 are both provided with threaded sections for threaded connection with the nuts f, and the nuts f and the rotor core 2 are insulated and abutted by a gasket g having an insulating function. Fig.11 The steps for installing the rotor core 2 on the rotating shaft 1 are as follows: first, the rotor core 2 is inserted into the metal sleeve 3 of the middle shaft section 12, and then the gaskets g are respectively inserted from both ends of the rotating shaft 1. Then, the nuts f are respectively screwed in from both ends of the rotating shaft 1 and tightened so that the two side surfaces of the rotor core 2 are respectively in contact with the two gaskets g. At this point, the rotor core 2 is installed and fixed to the rotating shaft 1.

[0071] The second embodiment also provides a motor, comprising the motor rotor as described above.

[0072] Embodiment 3

[0073] like Fig.12 , which is a third embodiment of the motor rotor of the present invention. Embodiment 3 is basically the same as Embodiment 1, and the similarities are not repeated here. The difference is that in this embodiment 3, the inner surfaces of the two end portions of the metal sleeve 3 are in contact with the outer surface of the middle shaft section 12, and a cavity d is formed between the inner surface of the middle portion of the metal sleeve 3 and the outer surface of the middle shaft section 12 to reduce the weight of the rotating shaft 1.

[0074] The third embodiment also provides a motor, comprising the motor rotor as described above.

[0075] Embodiment 4

[0076] like Fig.13 , which is a fourth embodiment of the motor rotor of the present invention. Embodiment 4 is basically the same as Embodiment 2, and the similarities are not repeated here, except that, in this embodiment 4, the inner surfaces of the two end portions of the metal sleeve 3 are in contact with the outer surface of the middle shaft section 12, and a cavity d is formed between the inner surface of the middle portion of the metal sleeve 3 and the outer surface of the middle shaft section 12 to reduce the weight of the rotating shaft 1.

[0077] The fourth embodiment also provides a motor, comprising the motor rotor as described above.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A motor rotor, comprising a rotating shaft (1) and a rotor core (2), characterized in that: The rotating shaft (1) comprises a front shaft section (11), a middle shaft section (12) and a rear shaft section (13); the two ends of the middle shaft section (12) are respectively insulated and connected to the front shaft section (11) and the rear shaft section (13); a metal sleeve (3) is sleeved and fixed on the middle shaft section (12); the two ends of the metal sleeve (3) are respectively insulated and connected to the two ends of the middle shaft section (12) and there is a gap between the front shaft section (11) and the rear shaft section (13); the rotor core (2) is sleeved on the metal sleeve (3); the front shaft section (11) and the rear shaft section (13) are respectively provided with a front shaft positioning member (111) and a rear shaft positioning member (131) at a position close to the middle shaft section (12); the front shaft positioning member (111) and the rear shaft positioning member (131) are respectively insulated and abutted against two side surfaces of the rotor core (2).

2. The motor rotor according to claim 1, characterized in that: The outer diameters of the two end portions of the metal sleeve (3) are smaller than the outer diameter of the middle portion of the metal sleeve (3), and the two end portions of the metal sleeve (3) are fixedly connected to the two ends of the middle shaft section (12) by winding insulating material (c).

3. The motor rotor according to claim 1, characterized in that: The inner surfaces of the two end portions of the metal sleeve (3) and the inner surface of the middle portion of the metal sleeve (3) are in contact with the outer surface of the middle shaft section (12).

4. The motor rotor according to claim 1, characterized in that: The inner surfaces of the two end portions of the metal sleeve (3) are in contact with the outer surface of the middle shaft section (12), and a cavity (d) is formed between the inner surface of the middle portion of the metal sleeve (3) and the outer surface of the middle shaft section (12).

5. The motor rotor according to claim 1, characterized in that: The cross-sectional shape of the outer contour of the metal sleeve (3) is non-circular, and the inner contour of the connecting hole on the rotor core (2) matches the shape of the outer contour of the metal sleeve (3).

6. The motor rotor according to claim 1, characterized in that: The cross-sectional shape of the middle shaft section (12) is non-circular, and the inner contour of the matching portion of the metal sleeve (3) and the middle shaft section (12) matches the outer contour of the middle shaft section (12).

7. The motor rotor according to claim 1, characterized in that: One of the front axle positioning member (111) and the rear axle positioning member (131) is an axial shoulder (e), and the other is a nut (f); a threaded section for threadedly cooperating with the nut (f) is provided on the front axle section (11) or the rear axle section (13); the axial shoulder (e) and the nut (f) are respectively insulated and abutted against two side surfaces of the rotor core (2).

8. The motor rotor according to claim 1, characterized in that: The front axle positioning member (111) and the rear axle positioning member (131) are both nuts (f), and the front axle section (11) and the rear axle section (13) are both provided with threaded sections for threadedly cooperating with the nuts (f), and the two side surfaces of the rotor core (2) are insulated and abutted against the two nuts (f) respectively.

9. The motor rotor according to claim 1, characterized in that: The rotor iron core (2) and the front axle positioning member (111), and the rotor iron core (2) and the rear axle positioning member (131) are both insulated and abutted by gaskets (g) having an insulating function.

10. A motor, characterized in that: It comprises a motor rotor as claimed in any one of claims 1 to 9.

Images