Motor rotor and motor

Abstract

This application discloses a motor rotor and a motor. The motor rotor includes a rotor core, multiple permanent magnets, and multiple conductor bars. The rotor core has multiple magnetic slots, which are spaced apart circumferentially along the rotor core. Each magnetic slot has a magnetic isolation slot at both ends. The multiple permanent magnets are respectively disposed in each magnetic slot, and the multiple conductor bars are respectively disposed in each magnetic isolation slot. By providing conductor bars at both ends of the permanent magnets, this application ensures that when the motor generates high-frequency current harmonics during operation, the eddy current generation area is mainly concentrated in the conductor bars due to the combined effects of the skin effect and the proximity effect. This reduces the eddy current loss of the permanent magnets in the motor rotor, lowers the temperature of the permanent magnets under the same operating conditions, and thus reduces the risk of demagnetization in the permanent magnet synchronous motor and improves the motor efficiency. Under the same operating conditions, the amount of permanent magnets used or the grade of permanent magnets can be reduced to lower the motor cost.

Description

Technical Field

[0001] This application relates to the field of synchronous motor technology, specifically to a motor rotor and a motor comprising the motor rotor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are widely used in new energy vehicle drives, wind power generation, aerospace, and other fields due to their high efficiency, high power density, and ease of control. However, when a PMSM operates at high speeds, the high-order harmonics generated by the stator winding current will induce eddy currents in the permanent magnet. Eddy current losses will cause the permanent magnet to heat up, leading to a decrease in motor efficiency. Furthermore, if the permanent magnet temperature rises further or the induced magnetic field strength on the rotor by the stator winding becomes too high, irreversible demagnetization of the permanent magnet may occur, severely affecting motor performance. Utility Model Content

[0003] In order to effectively overcome the problems existing in the prior art, the main objective of this application is to provide a motor rotor and motor that can reduce eddy current losses on permanent magnets.

[0004] To achieve the above objectives, this application specifically adopts the following technical solution:

[0005] This application provides a motor rotor, the motor rotor comprising:

[0006] The rotor core is provided with a plurality of magnetic slots, which are distributed at intervals along the circumference of the rotor core, and each magnetic slot is provided with a magnetic isolation slot at both ends.

[0007] Multiple permanent magnets, each of which is disposed within a specific magnetic groove; and

[0008] Multiple guide bars are disposed in each of the magnetic shielding grooves.

[0009] In some embodiments, the magnetic isolation grooves located at both ends of the magnetic steel groove are connected to the magnetic steel groove, and the guide bars located at both ends of the permanent magnet abut against both ends of the permanent magnet.

[0010] In some embodiments, each of the magnet slots is elongated, and the length extension direction of each magnet slot intersects the radial direction of the rotor core.

[0011] In some embodiments, the plurality of magnetic slots form multiple groups of magnetic slots, each group of magnetic slots includes at least two magnetic slots, and each group of magnetic slots is distributed at intervals along the circumference of the rotor core.

[0012] In some embodiments, each group of magnetic steel grooves includes four magnetic steel grooves, which are arranged in a triangular pattern.

[0013] In some embodiments, the permanent magnet is fixed to the magnetic groove by adhesive bonding.

[0014] In some embodiments, the conductor strip is bonded to the magnetically shielding groove by an adhesive, and the adhesive is conductive.

[0015] In some embodiments, the guide strip is made of a conductive material.

[0016] In some embodiments, the guide strip is made of metal powder.

[0017] Accordingly, this application also provides an electric motor, the electric motor comprising:

[0018] case;

[0019] Motor stator, the motor stator being disposed within the housing;

[0020] A rotating shaft, wherein the rotating shaft is disposed within the housing and partially extends outside the housing; and

[0021] As described in any of the above embodiments, the motor rotor is disposed within the housing and fixedly connected to the rotating shaft, and the motor rotor is capable of rotating relative to the motor stator.

[0022] The motor rotor of this application includes a rotor core, multiple permanent magnets, and multiple conductor bars. The rotor core has multiple magnetic slots, which are spaced apart circumferentially along the rotor core. Each magnetic slot has a magnetic isolation slot at both ends. The multiple permanent magnets are respectively disposed in each magnetic slot, and the multiple conductor bars are respectively disposed in each magnetic isolation slot. Compared with related technologies, this application, by providing conductor bars at both ends of the permanent magnets, ensures that when the motor generates high-frequency current harmonics during operation, the eddy current generation area is mainly concentrated in the conductor bars due to the combined effects of the skin effect and proximity effect. This reduces the eddy current loss of the permanent magnets in the motor rotor, lowers the temperature of the permanent magnets under the same operating conditions, and thus reduces the risk of demagnetization of the permanent magnet synchronous motor and improves motor efficiency. Under the same operating conditions, the amount of permanent magnets used or the grade of permanent magnets can be reduced to lower the motor cost. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the motor rotor provided in an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of the structure of the motor provided in an embodiment of this application.

[0025] Attached image labels:

[0026] 1. Rotor core; 11. Magnet slot; 12. Magnetic isolation slot; 2. Permanent magnet; 3. Conductor bar; 100. Motor; 101. Housing; 102. Shaft. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" used in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0030] A permanent magnet synchronous motor typically consists of a stator, a rotor, and a shaft. The stator has three-phase windings, each with a 120-degree phase difference. The rotor contains permanent magnets to generate a stable magnetic field. When the stator windings are excited by an AC power supply, a rotating magnetic field is generated. The permanent magnets on the rotor rotate synchronously due to the stator's magnetic field, driving the shaft to rotate. However, when the permanent magnet synchronous motor operates at high speeds, the high-order harmonics generated by the stator winding current induce eddy currents in the permanent magnets (eddy currents are closed currents generated within a conductor due to a changing magnetic field or conductor motion). Eddy current losses (energy losses caused by induced currents within the conductor) cause the permanent magnets to heat up, leading to reduced motor efficiency. Furthermore, if the permanent magnet temperature rises further or the induced magnetic field strength on the rotor is too high, irreversible demagnetization of the permanent magnets may occur, severely affecting motor performance.

[0031] In related technologies, to reduce eddy current losses in permanent magnets in rotors, a common method is to use segmented bonded permanent magnets. This involves dividing the permanent magnet into several small pieces along or perpendicular to the magnetization direction and then bonding them together. This approach can reduce eddy currents to some extent, but for the same volume, the overall performance of the permanent magnet will decrease, and the production cost will increase significantly. Some studies have also proposed increasing the magnetic reluctance to reduce eddy current losses in permanent magnets, but this approach will lead to varying degrees of performance degradation in the motor. Alternatively, increasing the thickness of the permanent magnet or improving its coercivity can increase the cost of the motor. Based on this, the inventors of this application propose a motor rotor for a permanent magnet synchronous motor that can reduce eddy current losses in permanent magnets.

[0032] Reference Figure 1 As shown, an embodiment of this application discloses a motor rotor that can be applied to a permanent magnet synchronous motor. The motor rotor includes a rotor core 1, multiple permanent magnets 2, and multiple guide bars 3. The rotor core 1 has multiple magnetic slots 11, which are spaced apart circumferentially along the rotor core 1. Each magnetic slot 11 has a magnetic isolation slot 12 at both ends, and the magnetic isolation slot 12 communicates with the magnetic slot 11. Multiple permanent magnets 2 are respectively disposed within each magnetic slot 11, and multiple guide bars 3 are respectively disposed within each magnetic isolation slot 12. The guide bars 3 located at both ends of the permanent magnets 2 abut against the two ends of the permanent magnets 2.

[0033] This application provides guide bars 3 at both ends of the permanent magnet 2, so that when the motor generates high-frequency current harmonics during operation, the eddy current generation area is mainly concentrated in the guide bars 3 under the combined effect of skin effect and proximity effect, thereby effectively improving the eddy current loss of the permanent magnet 2.

[0034] In some embodiments, each magnet slot 11 has an elongated structure, and the length extension direction of each magnet slot 11 intersects the radial direction of the rotor core 1.

[0035] In some embodiments, the plurality of magnetic slots 11 can form multiple groups of magnetic slots 11, each group of magnetic slots 11 including at least two magnetic slots 11, and each group of magnetic slots 11 is distributed at intervals along the circumference of the rotor core 1. Exemplarily, each group of magnetic slots 11 may include four magnetic slots 11, the four magnetic slots 11 forming a triangular arrangement, wherein the two shorter magnetic slots 11 in each group of magnetic slots 11 can be arranged approximately side by side as one side of the triangle, and the other two longer magnetic slots 11 can be the other two sides of the triangle.

[0036] In some embodiments, the permanent magnet 2 can be fixed in the magnetic steel groove 11 by adhesive bonding or by snap-fitting. The guide strip 3 can be fixed in the magnetic shielding groove 12 by adhesive bonding, and the adhesive can be conductive. For example, a modified substance can be added to the adhesive to make the modified adhesive conductive. The guide strip 3 can also be embedded in the magnetic shielding groove 12 by snap-fitting.

[0037] In some embodiments, the material of the conductor strip 3 can be a conductive material, such as silver, gold, copper, aluminum, iron, conductive fibers and their composites, or metal powder.

[0038] Accordingly, embodiments of this application also disclose an electric motor, with reference to... Figure 2 As shown, the motor 100 includes a housing 101, a shaft 102, a stator (not shown), and a rotor. The rotor can be any of the rotors described in the above embodiments. The stator is disposed within the housing 101 and includes windings. The shaft 102 is disposed within the housing 101 and partially extends outside the housing 101. The rotor is disposed within the housing 101 and fixedly connected to the shaft 102, and the rotor can rotate relative to the stator. When the windings on the stator are powered by AC, a rotating magnetic field is generated, and the permanent magnets on the rotor rotate synchronously due to the influence of the stator's magnetic field, thereby driving the rotor and shaft to rotate.

[0039] The motor rotor of this application has guide bars 3 at both ends of the permanent magnet 2, which allows the eddy current region generated by the motor stator during operation to be transferred from the corners of the permanent magnet 2 to the guide bars 3. This significantly reduces the eddy current loss of the permanent magnet 2 in the motor rotor, reduces the temperature of the permanent magnet 2 under the same operating conditions, thereby reducing the risk of demagnetization of the permanent magnet synchronous motor and improving the motor efficiency. Under the premise of meeting the same operating conditions, the amount of permanent magnet 2 used can be reduced or the grade of permanent magnet 2 can be lowered to reduce the cost of the motor.

[0040] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A motor rotor, characterized in that, include: The rotor core has multiple magnetic slots, which are spaced apart along the circumference of the rotor core, and each magnetic slot has a magnetic isolation slot at both ends. Multiple permanent magnets, each of which is disposed within a specific magnetic groove; and Multiple guide bars are disposed in each of the magnetic isolation grooves.

2. The motor rotor according to claim 1, characterized in that, The magnetic isolation grooves located at both ends of the magnetic steel groove are connected to the magnetic steel groove, and the guide bars located at both ends of the permanent magnet abut against both ends of the permanent magnet.

3. The motor rotor according to claim 2, characterized in that, Each of the magnetic slots is elongated, and the length of each magnetic slot extends in a direction that intersects the radial direction of the rotor core.

4. The motor rotor according to claim 3, characterized in that, The multiple magnetic slots form multiple sets of magnetic slots, each set of magnetic slots includes at least two magnetic slots, and each set of magnetic slots is distributed at intervals along the circumference of the rotor core.

5. The motor rotor according to claim 4, characterized in that, Each group of magnetic steel grooves includes four magnetic steel grooves, which are arranged in a triangular pattern.

6. The motor rotor according to claim 1, characterized in that, The permanent magnet is fixed in the magnetic steel groove by adhesive bonding.

7. The motor rotor according to claim 1, characterized in that, The conductor strip is bonded to the magnetic shielding groove with an adhesive, and the adhesive is conductive.

8. The motor rotor according to claim 1, characterized in that, The guide bar is made of a conductive material.

9. The motor rotor according to claim 1, characterized in that, The guide bar is made of metal powder.

10. An electric motor, characterized in that, include: case; Motor stator, the motor stator being disposed within the housing; A rotating shaft, wherein the rotating shaft is disposed inside the housing and partially protrudes outside the housing; and The motor rotor as described in any one of claims 1 to 9, wherein the motor rotor is disposed within the housing and fixedly connected to the rotating shaft, and the motor rotor is capable of rotating relative to the motor stator.

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