An electric motor rotor and an electric motor

Abstract

This utility model discloses a motor rotor and a motor. The motor rotor includes: a rotating shaft; a rotor core, and a plurality of rotor magnetic slots are provided on the end face of the rotor core. The plurality of rotor magnetic slots are arranged in a ring with the axis of the rotor core as the center. Each rotor magnetic slot contains a permanent magnet. A first hole is provided through the rotor core along its axial direction. A powder metallurgy layer is provided on the inner wall of the first hole. A second hole is provided through the powder metallurgy layer along its axial direction. The rotating shaft extends into the second hole to form a fixed fit. Compared with the prior art, this utility model, by providing a powder metallurgy layer inside the rotor core and using the powder metallurgy layer to fix the rotor core, only requires normal temperature assembly and does not require additional heating of the rotor core. This method saves production cycle time and avoids loosening of the fit between the rotor core and the rotating shaft.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and in particular to a motor rotor and a motor. Background Technology

[0002] For electric and hybrid vehicles, the connection between the rotor core and the shaft and the torque transmission are a key aspect of motor design, ensuring mechanical integrity and efficient torque transmission under various operating conditions.

[0003] In existing technology, the rotor core is heated to expand its inner diameter and then rapidly assembled onto the shaft. As the rotor core cools, it shrinks, creating a tight fit with the shaft. This method provides high mechanical strength and torque transmission efficiency.

[0004] During motor operation, high temperatures can cause the rotor core and shaft to expand at different rates. Over time, the fit between the rotor core and shaft may loosen. Utility Model Content

[0005] The purpose of this invention is to provide a motor rotor and a motor to solve the technical problems in the prior art, which can ensure a highly precise fit between the rotor core and the shaft.

[0006] In a first aspect, this utility model provides a motor rotor, comprising:

[0007] Shaft;

[0008] A rotor core, wherein a plurality of rotor magnetic slots are provided on the end face of the rotor core, the plurality of rotor magnetic slots being arranged in a ring at intervals around the axis of the rotor core, and each rotor magnetic slot containing a permanent magnet, wherein:

[0009] The rotor core has a first hole through it along its axial direction. The inner wall of the first hole is provided with a powder metallurgy layer. The powder metallurgy layer has a second hole through it along its axial direction. The rotating shaft extends into the second hole to form a fixed fit.

[0010] In the motor rotor described above, preferably, the outer circumferential surface of the rotating shaft is provided with a plurality of first protrusions, the plurality of first protrusions are arranged circumferentially at intervals around the axis of the rotating shaft, the first protrusions extend along the axial direction of the rotating shaft, the inner wall surface of the second hole is provided with a plurality of first grooves, the plurality of first grooves correspond one-to-one with the plurality of first protrusions, and the first protrusions extend into the first grooves to form a fixed fit.

[0011] In the motor rotor described above, preferably, the shaft is provided with a second groove, which is located between two adjacent first protrusions;

[0012] A second protrusion is provided on the inner wall surface of the first hole, and the second protrusion extends into the second groove to form a clearance fit.

[0013] In the motor rotor described above, preferably, multiple second slots are provided, and the multiple second slots are symmetrically arranged on the rotating shaft.

[0014] In the motor rotor described above, preferably, each group of rotor magnetic slots includes two rotor magnetic slots, each rotor magnetic slot having a first end and a second end. The first end of the rotor magnetic slot is closer to the axis of the rotor core than the second end, and the distance between the first ends of the two rotor magnetic slots is smaller than the distance between the second ends of the two rotor magnetic slots.

[0015] In the motor rotor described above, preferably, the rotor magnetic slots are waist-shaped slots.

[0016] In the motor rotor described above, preferably, an epoxy molding compound is further provided in the rotor magnetic slots, and the epoxy molding compound is disposed on opposite sides of the permanent magnet.

[0017] In the motor rotor described above, preferably, the rotating shaft is provided with a third protrusion, which is used to abut against the rotor core to restrict the axial movement of the rotor core.

[0018] In the motor rotor described above, preferably, a plurality of third holes are provided on the end face of the rotor core, and the plurality of third holes correspond one-to-one with a plurality of rotor magnetic slot groups, and the third holes axially penetrate the rotor core.

[0019] Secondly, this utility model provides an electric motor, including the aforementioned motor rotor.

[0020] Compared with the prior art, this utility model provides a powder metallurgy layer inside the rotor core and uses the powder metallurgy layer to fix and fit with the shaft, ensuring a high degree of precision fit between the rotor core and the shaft. This method saves production cycle time and can also prevent the fit between the rotor core and the shaft from becoming loose. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the motor rotor provided in this embodiment of the utility model;

[0022] Figure 2 This is a schematic diagram of the end face of the motor rotor provided in this embodiment of the utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 10-Shaft, 11-First protrusion, 12-Second groove, 13-Third protrusion;

[0025] 20-Rotor core, 21-Rotor slot, 22-Permanent magnet, 23-First hole, 24-Powder metallurgy layer, 25-Second hole, 26-First slot, 27-Second protrusion, 28-Epoxy molding compound, 29-Third hole. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] like Figure 1 and Figure 2 As shown, an embodiment of this utility model provides a motor rotor, including a rotating shaft 10 and a rotor core 20 sleeved on the rotating shaft 10. The rotating shaft 10 serves as a support and rotating component of the motor rotor, and the axes of the rotating shaft 10 and the rotor core 20 coincide.

[0028] The rotor core 20 has several rotor magnetic slot groups on its end face. The rotor magnetic slot groups are arranged in a ring with the axis of the rotor core 20 as the center. Each rotor magnetic slot group is provided with a permanent magnet 22. The permanent magnet 22 is used to generate a magnetic field and provide the necessary magnetic field conditions for the operation of the motor.

[0029] A first hole 23 is provided through the rotor core 20 along its axial direction. The inner diameter of the first hole 23 is larger than the outer diameter of the shaft 10. A powder metallurgy layer 24 is provided on the inner wall of the first hole 23. A second hole 25 is provided through the powder metallurgy layer 24 along its axial direction. The shaft 10 extends into the second hole 25 to form a fixed fit. The powder metallurgy layer 24 provides good mechanical properties and wear resistance, ensuring a firm connection between the shaft 10 and the rotor core 20. At the same time, the powder metallurgy layer 24 also plays a role in buffering and shock absorption.

[0030] As a manufacturing process that can be referenced, in the embodiment provided by this utility model, the rotor core 20 is made of multiple layers of silicon steel sheets to reduce eddy current losses and improve the efficiency of the motor. First, the stacked rotor core 20 is fitted onto the rotating shaft 10, which extends into the first hole 23. There is a receiving gap between the inner wall of the first hole 23 and the outer wall of the rotating shaft 10. Then, a material suitable for permanent magnet 22 is injected into the rotor magnetic groove 21 to form permanent magnet 22. Then, thermosetting materials such as powder metallurgy are injected into the first hole 23. After the powder metallurgy fills the receiving gap, it cools and solidifies to form a powder metallurgy layer 24. The cooled and solidified powder metallurgy layer 24 forms a fixed fit with the rotating shaft 10 to ensure a firm connection between the rotating shaft 10 and the rotor core 20.

[0031] Using the above molding method, assembly can be carried out at normal temperature without the need for additional heating of the rotor core 20. This method saves production cycle time and can prevent loosening of the fit between the rotor core 20 and the shaft 10, thereby enhancing the overall structural stability of the motor rotor. It can also ensure uniform material distribution and avoid uneven magnetic field or mechanical performance degradation caused by uneven material distribution.

[0032] In the embodiments provided by this utility model, reference is made to Figure 1 As shown, a plurality of first protrusions 11 are provided on the outer circumferential surface of the rotating shaft 10. The plurality of first protrusions 11 are arranged in a ring at intervals around the axis of the rotating shaft 10. The first protrusions 11 extend along the axial direction of the rotating shaft 10. The cross section of the first protrusion 11 along the radial direction of the rotating shaft 10 is square, trapezoidal, triangular or more shapes, which are not limited here.

[0033] The inner wall of the second hole 25 is provided with a plurality of first grooves 26. The inner contour surface of the first groove 26 is adapted to the outer contour surface of the first protrusion 11. The plurality of first grooves 26 correspond one-to-one with the plurality of first protrusions 11. The first protrusion 11 extends into the first groove 26 to form a fixed fit. The powder metallurgy layer 24 assembled with the rotating shaft 10 prevents relative rotation between the rotating shaft 10 and the rotor core 20 by mechanical fitting, thereby effectively transmitting torque, improving torque transmission efficiency, and ensuring the high precision and safe fit between the rotor core 20 and the rotating shaft 10, ensuring the normal operation of the motor. At the same time, since the first protrusion 11 and the first groove 26 are arranged in a ring interval, stress can be evenly distributed, stress concentration can be avoided, and the reliability and durability of the connection can be improved.

[0034] Furthermore, the rotating shaft 10 is provided with a second groove 12, which is located between two adjacent first protrusions 11, and the extension direction of the second groove 12 is parallel to the radial direction of the rotating shaft 10. A second protrusion 27 is provided on the inner wall surface of the first hole 23, and the outer contour surface of the second protrusion 27 is adapted to the inner contour surface of the second groove 12. The second protrusion 27 extends into the second groove 12 to form a clearance fit.

[0035] The engagement of the first protrusion 11 and the first groove 26 provides a secure mechanical fit, preventing relative rotation between the shaft 10 and the rotor core 20. The engagement of the second protrusion 27 and the second groove 12 further enhances the stability of the connection. Through this double engagement, the connection between the shaft 10 and the rotor core 20 is ensured to be even more secure.

[0036] Before the shaft 10 is inserted through the first hole 23 on the rotor core 20, the second protrusion 27 is aligned with the second groove 12. The second protrusion 27 serves as a guide and positioning element. The length of the second protrusion 27 extending out of the first hole 23 is longer than the depth of the second groove 12. After the bottom of the second protrusion 27 contacts the bottom wall of the second groove 12, a receiving gap is formed between the inner wall of the second hole 25 and the outer wall of the shaft 10 to allow for the injection of powder metallurgy material for forming.

[0037] The clearance fit formed between the second protrusion 27 and the second groove 12 can reduce stress concentration during assembly, avoid assembly difficulties or component damage caused by interference fit, and at the same time, during motor operation, the clearance fit can absorb a certain amount of thermal expansion and mechanical vibration, reducing stress accumulation caused by temperature changes or operating vibration.

[0038] Preferably, multiple second slots 12 are provided, and the multiple second slots 12 are symmetrically arranged on the rotating shaft 10. The number and position of the second protrusions 27 correspond to the number and position of the second slots 12. The symmetrical connection method can ensure that the rotating shaft 10 maintains good balance during rotation, making the assembly of the rotating shaft 10 and the rotor core 20 easier, reducing the alignment error during the assembly process, improving assembly efficiency, and reducing assembly difficulty.

[0039] In one feasible implementation, refer to Figure 2 As shown, there are two second grooves 12, which are symmetrically arranged on the rotating shaft 10. Correspondingly, there are also two second protrusions 27, which are symmetrically arranged on the inner wall of the first hole 23. The second protrusions 27 correspond to the second grooves 12.

[0040] In the embodiments provided by this utility model, reference is made to Figure 2 As shown, each set of rotor magnetic slots includes two rotor magnetic slots 21 to ensure the uniformity of magnetic field distribution. The rotor magnetic slot 21 includes a first end and a second end. The first end of the rotor magnetic slot 21 is closer to the axis of the rotor core 20 than the second end. The distance between the first ends of the two rotor magnetic slots 21 is smaller than the distance between the second ends of the two rotor magnetic slots 21.

[0041] The rotor magnetic slots 21 are shaped like a "trumpet," gradually widening from the first end to the second. The slots are more compact near the axis and more dispersed away from the axis, thus optimizing the magnetic field distribution. This concentrates the magnetic field near the axis, improving its strength and uniformity. Simultaneously, it reduces eddy current losses. Because the magnetic field is more concentrated near the axis, the eddy current path is effectively shortened, reducing eddy current losses and improving motor efficiency.

[0042] Furthermore, the rotor magnetic slot 21 is an oblong slot. That is, the cross-section of the rotor magnetic slot 21 along the radial direction of the rotating shaft 10 is similar to an elongated ellipse or rectangle, which allows the permanent magnet 22 to be better embedded in it. The oblong slot provides sufficient space for fixing and installation. At the same time, because it is narrower at both ends and wider in the middle, the magnetic field can be more effectively concentrated at both ends of the permanent magnet 22, thereby improving the strength and uniformity of the magnetic field.

[0043] In one feasible implementation, refer to Figure 2 As shown, an epoxy molding compound 28 is also provided in the rotor magnetic slot 21. Along the long axis of the slot, the epoxy molding compound 28 is disposed on opposite sides of the permanent magnet 22, forming a stable structure. The epoxy molding compound 28 has high strength, high insulation and good adhesion, which can firmly fix the permanent magnet 22 in the rotor magnetic slot 21, preventing the permanent magnet 22 from loosening or falling off due to vibration or centrifugal force during motor operation. At the same time, it can prevent short circuits or arc discharges between the permanent magnet 22 and the rotor core 20, thereby improving the reliability and service life of the motor.

[0044] In the embodiments provided by this utility model, reference is made to Figure 1 As shown, the rotating shaft 10 is provided with a third protrusion 13, which is preferably located at the end of the first protrusion 11. The third protrusion 13 is used to abut against the rotor core 20 to limit the axial movement of the rotor core 20, thereby ensuring that the rotor core 20 remains stable during motor operation and preventing the rotor core 20 from undergoing axial displacement due to vibration or impact during motor operation, thus avoiding failures caused by axial displacement.

[0045] The shape of the third protrusion 13 can be annular, circular, or other suitable, depending on the design of the shaft 10 and the rotor core 20. The height and width of the third protrusion 13 need to be designed according to actual requirements to ensure that it can effectively restrict the axial movement of the rotor core 20.

[0046] Reference Figure 2As shown, the rotor core 20 has several third holes 29 on its end face, which axially penetrate the rotor core 20. These third holes 29 serve as heat dissipation channels; during motor operation, heat can be dissipated into the surrounding environment through the channels of the third holes 29, thereby reducing the temperature of the rotor core 20 and improving the motor's heat dissipation performance. Simultaneously, the third holes 29 can reduce the weight of the rotor core 20 and decrease its moment of inertia. Each of the third holes 29 corresponds one-to-one with a set of rotor magnetic slots to optimize the magnetic field distribution and reduce magnetic field inhomogeneity.

[0047] Those skilled in the art will know that the shape of the third hole 29 is usually circular or other suitable shape, depending on the actual needs. The size of the third hole 29 needs to be designed according to the actual needs to ensure that it can meet specific functional requirements.

[0048] Based on the motor rotor provided in the above embodiments, this utility model also provides a motor, including a stator, an end cover, and the aforementioned motor rotor. The stator has an annular structure with multiple mounting slots evenly distributed on it. Enamelled wire is installed in the mounting slots. The end cover is located at the end of the stator, and the motor rotor is rotatably supported within the stator, with a rotating shaft extending from the end cover. Since the motor provided in this embodiment includes the aforementioned motor rotor, it possesses the aforementioned technical effects of the motor rotor, which will not be elaborated further here.

[0049] The above description, based on the embodiments shown in the drawings, details the structure, features, and effects of this utility model. The above description is only a preferred embodiment of this utility model, but the scope of implementation of this utility model is not limited to what is shown in the drawings. Any changes made in accordance with the concept of this utility model, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and drawings, shall be within the protection scope of this utility model.

Claims

1. An electric motor rotor, comprising: Shaft; A rotor core, wherein a plurality of rotor magnetic slots are provided on the end face of the rotor core, the plurality of rotor magnetic slots are arranged in a ring at intervals around the axis of the rotor core, and each rotor magnetic slot is provided with a permanent magnet, characterized in that: The rotor core has a first hole through it along its axial direction. The inner wall of the first hole is provided with a powder metallurgy layer. The powder metallurgy layer has a second hole through it along its axial direction. The rotating shaft extends into the second hole to form a fixed fit.

2. The electric machine rotor of claim 1, wherein, The outer circumferential surface of the rotating shaft is provided with a plurality of first protrusions, which are arranged circumferentially at intervals around the axis of the rotating shaft. The first protrusions extend along the axis of the rotating shaft. The inner wall surface of the second hole is provided with a plurality of first grooves, which correspond one-to-one with the plurality of first protrusions. The first protrusions extend into the first grooves to form a fixed fit.

3. The motor rotor of claim 2, wherein, The rotating shaft is provided with a second groove, which is located between two adjacent first protrusions; A second protrusion is provided on the inner wall surface of the first hole, and the second protrusion extends into the second groove to form a clearance fit.

4. The motor rotor of claim 3, wherein The second groove is provided in multiple ways, and the multiple second grooves are symmetrically arranged on the rotating shaft.

5. The motor rotor of claim 1, wherein Each set of rotor magnetic slots includes two rotor magnetic slots, each rotor magnetic slot having a first end and a second end. The first end of the rotor magnetic slot is closer to the axis of the rotor core than the second end, and the distance between the first ends of the two rotor magnetic slots is less than the distance between the second ends of the two rotor magnetic slots.

6. The motor rotor of claim 5, wherein, The rotor magnetic slots are waist-shaped slots.

7. The motor rotor of claim 6, wherein The rotor magnetic slot is also provided with an epoxy molding compound, which is disposed on opposite sides of the permanent magnet.

8. The motor rotor of claim 1, wherein The rotating shaft is provided with a third protrusion, which is used to abut against the rotor core to restrict the axial movement of the rotor core.

9. The motor rotor according to claim 1, characterized in that, The rotor core has a plurality of third holes on its end face, and the plurality of third holes correspond one-to-one with the plurality of rotor magnetic slots. The third holes axially penetrate the rotor core.

10. An electric machine characterized by Includes the motor rotor as described in any one of claims 1-9.

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