Motor Rotor and Motor

Abstract

The present application provides a motor rotor and a motor. The motor rotor includes a rotating shaft (1) and a permanent magnet (2). The rotating shaft (1) is provided with a mounting hole (3), and the permanent magnet (2) is mounted in the mounting hole (3). A first stop structure is provided at the first end of the permanent magnet (2), and a second stop structure is provided at the second end of the permanent magnet (2). According to the motor rotor of the present application, it is possible to reduce or avoid external interference on the permanent magnet and effectively protect the permanent magnet.

Description

Technical Field

[0001] This application relates to the technical field of motor equipment, and particularly relates to a motor rotor and a motor. Background Art

[0002] Due to the high rotational speed of high-speed motors, the rotor is subjected to a very large centrifugal force during operation. Especially for permanent magnets, this problem is more prominent because the sintered permanent magnet materials cannot withstand the tensile stress generated by high-speed rotation. Therefore, protective measures must be taken for the permanent magnets. A most common protective measure is to thermally install an alloy sheath outside the permanent magnet, and the compressive stress generated by interference fit is used to offset the centrifugal force generated by high-speed rotation to protect the permanent magnet. However, although the structure of this kind of rotor is simple, its integrity is relatively general, its height is small, and the rotating shaft is prone to bending deformation during abnormal impact.

[0003] To solve this problem, a high-speed motor hollow shaft rotor structure has been proposed in the prior art, in which the permanent magnet is embedded inside the hollow shaft, improving the integrity of the rotor. However, the permanent magnet of this rotor structure is exposed outside, so it is easily interfered by the outside world and is prone to damage. Summary of the Invention

[0004] Therefore, the technical problem to be solved by this application is to provide a motor rotor and a motor that can reduce or avoid interference of the permanent magnet by the outside world and effectively protect the permanent magnet.

[0005] To solve the above problems, this application provides a motor rotor, including a rotating shaft and a permanent magnet. The rotating shaft is provided with an installation hole, and the permanent magnet is installed in the installation hole. A first stop structure is provided at the first end of the permanent magnet, and a second stop structure is provided at the second end of the permanent magnet.

[0006] Preferably, the installation hole is opened at one end of the rotating shaft. The first stop structure includes a stop surface located at the end of the installation hole, and the second stop structure includes a stop member located on the side of the permanent magnet away from the stop surface.

[0007] Preferably, the stop member is a baffle plate adapted to the shape of the installation hole, and the baffle plate is fixedly installed in the installation hole.

[0008] Preferably, the rotating shaft is provided with a first cooling hole, the permanent magnet is provided with a second cooling hole, and the baffle plate is provided with a third cooling hole. The first cooling hole, the second cooling hole, and the third cooling hole penetrate axially.

[0009] Preferably, the diameter of the second cooling hole is φ3, and 2mm ≤ φ3 ≤ 5mm.

[0010] Preferably, the diameter φ4 of the third cooling hole is greater than the diameter φ3 of the second cooling hole.

[0011] Preferably, 3mm ≤ Φ4 - Φ3 ≤ 5mm.

[0012] Preferably, the diameter φ2 of the first cooling hole is greater than the diameter φ3 of the second cooling hole.

[0013] Preferably, 3mm ≤ Φ2 - Φ3 ≤ 5mm.

[0014] Preferably, the mounting hole includes a first hole section and a second hole section, the second hole section is located outside the first hole section, and the permanent magnet and the stopper are mounted in the first hole section.

[0015] Preferably, the diameter of the first hole section is φ1, the tolerance is (a, b), the diameter of the second hole section is φ1, the tolerance is (c, d), and c > b.

[0016] Preferably, 0.5mm ≤ c - b ≤ 0.6mm.

[0017] Preferably, a groove extending circumferentially is provided on the outer periphery of the rotating shaft corresponding to the permanent magnet.

[0018] Preferably, the groove is a spiral groove, and the axial length of the spiral groove is greater than or equal to the axial length of the permanent magnet.

[0019] Preferably, the groove is filled with a heat-conducting material.

[0020] Preferably, a shielding layer is sleeved outside the rotating shaft.

[0021] Preferably, the shielding layer is a copper shielding layer, and the thickness of the copper shielding layer is 0.5mm to 1mm.

[0022] According to another aspect of the present application, a motor is provided, including a motor rotor, and the motor rotor is the above-mentioned motor rotor.

[0023] The motor rotor provided by the present application includes a rotating shaft and a permanent magnet. The rotating shaft is provided with a mounting hole, the permanent magnet is mounted in the mounting hole, a first stopper structure is provided at the first end of the permanent magnet, and a second stopper structure is provided at the second end of the permanent magnet. The motor rotor is provided with stopper structures at both ends of the permanent magnet. On the one hand, it can form good axial stopper and limit for the permanent magnet, prevent the permanent magnet from coming out of the rotating shaft, and improve the stability of the permanent magnet mounting structure. On the other hand, it can protect the permanent magnet by using the stopper structure to avoid damage to the permanent magnet due to exposure to external interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic cross-sectional structure view of a motor rotor according to an embodiment of the present application;

[0025] Figure 2 is a schematic cross-sectional view of the rotating shaft of the motor rotor according to an embodiment of the present application;

[0026] Figure 3Cross-sectional structure diagram of the permanent magnet of the motor rotor according to an embodiment of the present application;

[0027] Figure 4 Cross-sectional structure diagram of the stopper of the motor rotor according to an embodiment of the present application;

[0028] Figure 5 Cross-sectional structure diagram of the motor according to an embodiment of the present application.

[0029] The reference numerals are shown as:

[0030] 1, rotating shaft; 2, permanent magnet; 3, mounting hole; 4, stop surface; 5, stopper; 6, first cooling hole; 7, second cooling hole; 8, third cooling hole; 9, first hole section; 10, second hole section; 11, spiral groove; 12, shielding layer; 13, stator; 14, housing; 15, front end cover; 16, rear end cover; 17, bearing. Detailed implementation manners

[0031] Referring to Figures 1 to 5 As shown, according to an embodiment of the present application, the motor rotor includes a rotating shaft 1 and a permanent magnet 2. The rotating shaft 1 is provided with a mounting hole 3, and the permanent magnet 2 is installed in the mounting hole 3. A first stop structure is provided at the first end of the permanent magnet 2, and a second stop structure is provided at the second end of the permanent magnet 2.

[0032] The motor rotor is provided with stop structures at both ends of the permanent magnet 2. On the one hand, it can form a good axial stop limit for the permanent magnet 2, prevent the permanent magnet 2 from coming out of the rotating shaft 1, improve the stability of the installation structure of the permanent magnet 2, and prevent the permanent magnet 2 from axially moving. On the other hand, it can use the stop structure to protect the permanent magnet 2 and avoid damage to the permanent magnet 2 due to exposure to external interference.

[0033] In an embodiment, the mounting hole 3 is opened at one end of the rotating shaft 1. The first stop structure includes a stop surface 4 at the end of the mounting hole 3, and the second stop structure includes a stopper 5 on the side of the permanent magnet 2 away from the stop surface 4. In this embodiment, since the mounting hole 3 is opened at one end of the rotating shaft 1 and does not axially penetrate the rotating shaft 1, the stop surface 4 of the rotating shaft 1 itself can be used to form a stop structure for axially stopping the permanent magnet 2. The structure is simple, the installation is convenient, and the processing procedure is less, the processing amount is smaller, and the processing cost is lower. By providing the stopper 5 on the opening side of the mounting hole 3, after the permanent magnet 2 is installed in the mounting hole 3, the stopper 5 can be installed to axially limit the permanent magnet 2, which is convenient for installing the permanent magnet 2.

[0034] In this embodiment, the mounting hole 3 is provided at one end of the rotating shaft 1 away from the shaft extension end, so that the end of the rotating shaft 1 as the shaft extension end has higher structural strength, which is convenient for designing the shaft extension end structure to realize connection with other components or hanging other components.

[0035] In one embodiment, the stopper 5 is a baffle plate adapted to the shape of the mounting hole 3, and the baffle plate is fixedly installed in the mounting hole 3. In this embodiment, a baffle plate is used as the stopper 5, and its structure is adapted to the shape of the mounting hole 3. Not only is the structure easy to process, saving materials and facilitating the cooperation with the mounting hole 3, but it can also effectively shield and protect the permanent magnet 2. The permanent magnet 2 and the baffle plate are, for example, in interference fit with the mounting hole 3.

[0036] In one embodiment, a first cooling hole 6 is provided on the rotating shaft 1, a second cooling hole 7 is provided on the permanent magnet 2, and a third cooling hole 8 is provided on the baffle plate. The first cooling hole 6, the second cooling hole 7, and the third cooling hole 8 penetrate axially, and an axial through hole can be formed in the central part of the motor rotor for ventilating and cooling the permanent magnet 2, facilitating the ventilation and heat dissipation of the permanent magnet 2.

[0037] In one embodiment, the diameter of the second cooling hole 7 is φ3, and 2mm ≤ φ3 ≤ 5mm. The limit of 2mm ≤ Φ3 ≤ 5mm is because if Φ3 is particularly small, the amount of heat exchange fluid flowing through the inside of the permanent magnet 2 will be relatively small, reducing the cooling effect. And if Φ3 is particularly large, magnetic leakage is likely to occur inside the permanent magnet 2, resulting in the inability to exert magnetic properties. Therefore, it is more reasonable to limit 2mm ≤ Φ3 ≤ 5mm.

[0038] In one embodiment, the diameter φ4 of the third cooling hole 8 is larger than the diameter φ3 of the second cooling hole 7. With this structure, the part of the end face of the permanent magnet 2 can be exposed by taking advantage of the fact that the diameter of the third cooling hole 8 is larger than that of the second cooling hole 7, thus facilitating the real-time monitoring of the temperature of the permanent magnet 2 using a temperature measuring tool such as a temperature gun, which is very convenient.

[0039] As a preferred embodiment, 3mm ≤ Φ4 - Φ3 ≤ 5mm. The limit of 3mm ≤ Φ4 - Φ3 ≤ 5mm is because if Φ4 is much larger than Φ3, the uncompacted area of the end face of the permanent magnet 2 will be larger, which is not conducive to the axial protection of the permanent magnet 2; while if Φ4 is only slightly larger than Φ3, the area of the end face of the permanent magnet 2 exposed to the air will be very small, which is not conducive to irradiating the end of the permanent magnet 2 with a temperature gun for testing.

[0040] In one embodiment, the diameter φ2 of the first cooling hole 6 is larger than the diameter φ3 of the second cooling hole 7.

[0041] As a preferred embodiment, 3mm ≤ Φ2 - Φ3 ≤ 5mm. The limitation of the relationship between Φ2 and Φ3 has the same effect as the limitation of the relationship between Φ4 and Φ3.

[0042] In one embodiment, the mounting hole 3 includes a first hole section 9 and a second hole section 10. The second hole section 10 is located outside the first hole section 9. The permanent magnet 2 and the stopper 5 are installed in the first hole section 9. The diameter of the second hole section 10 is greater than that of the first hole section 9, or the diameter of the second hole section 10 is the same as that of the first hole section 9, and the tolerance zone of the second hole section 10 is greater than that of the first hole section 9. The aperture size of the second hole section 10 is larger than that of the first hole section 9, which can reduce the difficulty in assembling the permanent magnet 2 and the baffle, and improve the installation convenience.

[0043] In one embodiment, the diameter of the first hole section 9 is φ1, the tolerance is (a, b), the diameter of the second hole section 10 is φ1, and the tolerance is (c, d), where c > b.

[0044] As a preferred embodiment, 0.5 mm ≤ c - b ≤ 0.6 mm. Limiting c - b is mainly for the convenience of assembly. Since the axial distance of the hollow part inside the rotating shaft is relatively long, and the interference fit region with the permanent magnet 2 is only a small section, there is no mating relationship in other regions and no excessive machining is required. At the same time, it is better to enlarge the size a little, so that the permanent magnet 2 will not be stuck during the assembly process. If the tolerance of this part of the region is completely the same as that of the section mating with the permanent magnet 2, on the one hand, it will increase the processing cost, and on the other hand, it is easy to cause the situation that the permanent magnet 2 is not assembled in place after the short shaft cools down and is stuck in the middle position. Enlarging this part of the size is beneficial to reducing the risk of assembly failure.

[0045] In one embodiment, a groove extending circumferentially is provided on the outer periphery of the rotating shaft 1 corresponding to the permanent magnet 2, which can optimize the surface structure of the rotating shaft 1 and reduce the eddy current loss of the motor rotor. The groove can extend only circumferentially along the rotating shaft 1 to form an annular groove or an arc groove, or can extend both circumferentially and axially along the rotating shaft 1 to form a spiral groove.

[0046] Preferably, the groove is a spiral groove 11, and the axial length of the spiral groove 11 is greater than or equal to the axial length of the permanent magnet 2.

[0047] In one embodiment, the groove is filled with a heat-conducting material, such as heat-conducting glue. On the one hand, it can improve the heat dissipation effect of the motor rotor, and on the other hand, it can enhance the structural strength of the rotating shaft 1.

[0048] In one embodiment, a shielding layer 12 is sleeved outside the rotating shaft 1, which can shield high-order harmonics significantly and reduce the heat generation of the permanent magnet 2.

[0049] Preferably, the shielding layer 12 is a copper shielding layer, and the thickness of the copper shielding layer is 0.5 mm to 1 mm. The thickness of the shielding layer 12 being 0.5 mm to 1 mm is the best. If it is too small, it cannot achieve the shielding effect, and if it is too large, the eddy current loss generated by itself will also increase, which will have a counterproductive effect.

[0050] When assembling, the hollow rotating shaft 1 needs to be heated to an appropriate temperature first, and then the permanent magnet 2 and the baffle are quickly inserted in sequence. After the rotating shaft 1 is completely cooled, the shielding layer 12 is sleeved, and both sides are connected and fixed to the rotating shaft 1 by welding. The assembly methods of the remaining components are more conventional and will not be elaborated here.

[0051] In the motor rotor structure of the present application, the rotating shaft 1 is a hollow shaft without segmentation, solving the problem of insufficient stiffness; at the same time, the permanent magnet 2 is directly embedded inside the hollow shaft, eliminating the alloy sheath or carbon fiber sheath, greatly saving costs; moreover, the hollow part inside the hollow shaft is divided into two sections. One section has a small-diameter hollow area, which is convenient for designing the shaft extension end structure and axially positioning one end of the permanent magnet 2 to prevent the permanent magnet 2 from being damaged axially. The other section has a large-diameter hollow area, which is convenient for directly embedding the permanent magnet 2 and the baffle; on the other hand, spiral grooves 11 are provided on the outer circle of the hollow shaft, reducing the eddy current loss of the rotor, and the spiral grooves 11 are filled with thermal conductive glue, which not only enhances the structural strength but also improves the heat dissipation effect. Finally, a hollow copper shielding layer is sleeved outside the hollow shaft, effectively shielding the high-order harmonics penetrating into the permanent magnet 2, further reducing the eddy current loss of the permanent magnet 2 itself, and controlling the heat generation of the permanent magnet 2 at an extremely low level. In addition, there is a small through hole at the center of the permanent magnet 2 for ventilation and cooling, and the two end faces are directly exposed, so a temperature measuring gun can be used to directly measure the temperature in real time, which is very simple and convenient.

[0052] According to an embodiment of the present application, the motor includes a motor rotor, and the motor rotor is the above-mentioned motor rotor.

[0053] The motor further includes a stator 13, a housing 14, a front end cover 15, a rear end cover 16, and bearings 17. The stator 13 is fixedly installed inside the housing 14, the motor rotor is installed inside the stator 13, and both ends of the motor rotor are rotatably installed inside the front end cover 15 and the rear end cover 16 through the bearings 17.

[0054] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned advantageous ways can be freely combined and superimposed.

[0055] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the technical principle of the present application, several improvements and modifications can still be made, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A motor rotor, characterized in that, It includes a rotating shaft (1) and a permanent magnet (2). The rotating shaft (1) is provided with a mounting hole (3), and the permanent magnet (2) is installed in the mounting hole (3). A first stop structure is provided at the first end of the permanent magnet (2), and a second stop structure is provided at the second end of the permanent magnet (2); the mounting hole (3) is opened at one end of the rotating shaft (1). The first stop structure includes a stop surface (4) located at the end of the mounting hole (3), and the second stop structure includes a stop member (5) located on the side of the permanent magnet (2) away from the stop surface (4); the rotating shaft (1) is of an integral structure. The mounting hole (3) includes a first hole section (9) and a second hole section (10). The second hole section (10) is located outside the first hole section (9). The permanent magnet (2) and the stop member (5) are installed in the first hole section (9), and the inner diameter of the second hole section (10) is larger than the inner diameter of the first hole section (9).

2. The motor rotor according to claim 1, wherein, The stop member (5) is a baffle plate adapted to the shape of the mounting hole (3), and the baffle plate is fixedly installed in the mounting hole (3).

3. The motor rotor according to claim 2, characterized in that, A first cooling hole (6) is provided on the rotating shaft (1), a second cooling hole (7) is provided on the permanent magnet (2), and a third cooling hole (8) is provided on the baffle plate. The first cooling hole (6), the second cooling hole (7) and the third cooling hole (8) penetrate axially.

4. The motor rotor according to claim 3, characterized in that, The diameter of the second cooling hole (7) is φ3, and 2mm ≤ φ3 ≤ 5mm.

5. The motor rotor according to claim 3, characterized in that, The diameter φ4 of the third cooling hole (8) is larger than the diameter φ3 of the second cooling hole (7).

6. The motor rotor according to claim 5, wherein, 3mm ≤ Φ4 - Φ3 ≤ 5mm.

7. The motor rotor according to claim 3, characterized in that, The diameter φ2 of the first cooling hole (6) is larger than the diameter φ3 of the second cooling hole (7).

8. The motor rotor according to claim 7, characterized in that, 3mm ≤ Φ2 - Φ3 ≤ 5mm.

9. The motor rotor according to claim 1, characterized in that, The diameter of the first hole section (9) is φ1, and the tolerance is (a, b). The diameter of the second hole section (10) is φ1, and the tolerance is (c, d), and c > b.

10. The motor rotor according to claim 9, characterized in that, 0.5mm ≤ c - b ≤ 0.6mm.

11. The motor rotor according to claim 1, characterized in that, A groove extending circumferentially is provided on the outer periphery of the rotating shaft (1) corresponding to the permanent magnet (2).

12. The motor rotor according to claim 11, characterized in that, The groove is a spiral groove (11), and the axial length of the spiral groove (11) is greater than or equal to the axial length of the permanent magnet (2).

13. The motor rotor according to claim 11, characterized in that, The groove is filled with a heat-conducting material.

14. The motor rotor according to claim 1, characterized in that, A shielding layer (12) is sleeved outside the rotating shaft (1).

15. The motor rotor according to claim 14, characterized in that, The shielding layer (12) is a copper shielding layer, and the thickness of the copper shielding layer is 0.5mm to 1mm.

16. A motor, comprising a motor rotor, characterized in that, The motor rotor is the motor rotor according to any one of claims 1 to 15.

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