Rotor core, asynchronous motor rotor and asynchronous motor

Abstract

The invention provides a rotor iron core, an asynchronous motor rotor and an asynchronous motor, the rotor iron core comprises at least two annular sub-iron cores which are adjacently arranged along the axial direction of the rotor, grooves are uniformly formed in the outer peripheries of the sub-iron cores along the circumferential direction, and the grooves are formed in the outer peripheries of the sub-iron cores. The rotor iron core is characterized in that the rotor iron core comprises a plurality of sub-iron cores, the sub-iron cores are provided with grooves, the grooves extend in a manner of twisting at an angle relative to the axial direction, the grooves of all the sub-iron cores form rotor grooves, and the rotor grooves are in a V shape or in a shape in which a plurality of V shapes are connected side by side in the axial direction. Torsional vibration caused by axial space phase asymmetry can be eliminated, and the vibration noise performance of the asynchronous motor and the consistency of the NVH performance of the asynchronous motor can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of asynchronous motors, and in particular to a rotor core, an asynchronous motor rotor and an asynchronous motor. Background Art

[0002] With the development of new energy vehicle technology, the application of automotive drive motors is becoming more and more extensive. At present, automotive drive motors mainly include permanent magnet synchronous motors and asynchronous induction motors. Asynchronous induction motors have obvious cost advantages due to the elimination of magnetic steel materials, and are mostly used as auxiliary drive motors in the vehicle's four-wheel drive system. In particular, due to the promotion of 800V high-voltage platforms in electric vehicles, the performance of the main drive motor has been improved. The driving solutions of the main drive permanent magnet motor and the auxiliary drive asynchronous motor can also achieve higher performance. Therefore, the application of asynchronous motors in the vehicle's four-wheel drive system is becoming more and more important.

[0003] However, compared with permanent magnet motors, asynchronous motors have more noise orders, and the casting quality consistency of the rotor is difficult to control and detect, which leads to vibration and noise problems and NVH consistency problems of batch parts. Unlike permanent magnet motor rotors, methods such as grooves on the outer edge of the rotor core and asymmetric magnetic poles to reduce electromagnetic radial force are not suitable for cast aluminum rotors of asynchronous motors.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] One aspect of the present application is to solve a technical problem of how to improve the NVH performance of an asynchronous motor rotor.

[0006] In addition, other aspects of the present application are also intended to solve or alleviate other technical problems existing in the prior art.

[0007] The present application provides a rotor core, an asynchronous motor rotor and an asynchronous motor. Specifically, according to one aspect of the present application, the present application provides:

[0008] A rotor core, wherein the rotor core comprises at least two annular sub-cores arranged adjacent to each other in the axial direction of the rotor, grooves are uniformly constructed in the circumferential direction on the outer periphery of the sub-cores, the grooves extend at a twisted angle relative to the axial direction, the grooves of all the sub-cores form rotor slots, and the rotor slots have a V-shape or a plurality of V-shapes connected side by side in the axial direction.

[0009] Optionally, according to an embodiment of the present application, the V-shaped angle satisfies the following formula:

[0010]

[0011] Among them, β is the V-shaped angle, L is the axial length of the rotor, R is the radius of the rotor, α is the circumferential spacing angle between two adjacent stator slots or two adjacent rotor slots, and k is the correction coefficient.

[0012] Optionally, according to one embodiment of the present application, the rotor core includes a first sub-core, a second sub-core, a third sub-core and a fourth sub-core which are arranged adjacent to each other in sequence along the axial direction, the four sub-cores have the same structure, the rotor slots have a V-shape in the axial direction, the grooves of the first sub-core and the second sub-core form one side of the V-shape, the third sub-core and the fourth sub-core form the other side of the V-shape, and the two sides of the V-shape are symmetrical to each other in the axial direction.

[0013] Optionally, according to one embodiment of the present application, the rotor core includes a first sub-core, a second sub-core, a third sub-core and a fourth sub-core which are arranged adjacent to each other in sequence along the axial direction, the four sub-cores have the same structure, and the rotor slots have two V-shaped shapes connected side by side in the axial direction, the grooves of the first sub-core and the second sub-core form a V-shape, the third sub-core and the fourth sub-core form a V-shape, and the two V-shapes are symmetrical to each other in the axial direction.

[0014] Optionally, according to one embodiment of the present application, the rotor core includes a first sub-core, a second sub-core, a third sub-core, a fourth sub-core, a fifth sub-core and a sixth sub-core which are arranged adjacent to each other in sequence along the axial direction, the six sub-cores have the same structure, and the rotor slots have three V-shaped shapes connected side by side in the axial direction, the grooves of the first sub-core and the second sub-core form a V-shape, the third sub-core and the fourth sub-core form a V-shape, the fifth sub-core and the sixth sub-core form a V-shape, and the three V-shapes are symmetrical about the center of the V-shape in the middle in the axial direction.

[0015] Optionally, according to an embodiment of the present application, a torsion angle of the groove relative to the axial direction is equal to a spacing angle between two adjacent grooves in the circumferential direction.

[0016] According to the second aspect of the present application, the present application provides an asynchronous motor rotor, wherein the asynchronous motor rotor includes the rotor core and squirrel cage described above, the squirrel cage includes guide bars and end rings connected at both ends of the guide bars, the guide bars are arranged in the rotor slots in a shape matching the rotor slots, and the end rings are arranged at both ends of the rotor core.

[0017] Optionally, according to an implementation of the second aspect of the present application, the squirrel cage is integrally formed by a centrifugal casting process.

[0018] Optionally, according to an implementation of the second aspect of the present application, the porosity between adjacent conductive bars is less than or equal to 2%.

[0019] According to a third aspect of the present application, the present application provides an asynchronous motor, wherein the asynchronous motor comprises the asynchronous motor rotor described above.

[0020] Benefits of this application include:

[0021] 1. In one embodiment of the present application, the rotor slots of the rotor core are designed in a V-shape in the axial direction, which can weaken the tooth harmonic magnetic field and reduce the amplitude of the electromagnetic radial force. The V-shaped rotor slots are especially designed symmetrically in the axial direction, which can eliminate the torsional vibration caused by the axial spatial phase asymmetry and improve the vibration and noise performance of the asynchronous motor.

[0022] 2. The squirrel cage of the asynchronous motor rotor proposed in one embodiment of the present application is manufactured by a centrifugal casting process, which can reduce the porosity defects of the guide bars and the end rings and limit the porosity between adjacent guide bars to within 2%, thereby ensuring the consistency of the guide bar casting quality as much as possible and avoiding the occurrence of unbalanced magnetic pull, thereby improving the NVH consistency of the asynchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] With reference to the accompanying drawings, the above and other features of the present application will become apparent. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. In addition, similar numbers in the figures are used to represent similar components, among which,

[0024] Figure 1 A schematic structural diagram of a rotor core according to an embodiment of the present application is shown;

[0025] Figure 2 A schematic diagram showing the structure of a rotor core installed on a rotor according to another embodiment of the present application is shown;

[0026] Figure 3 A schematic diagram showing the structure of an asynchronous motor rotor according to an embodiment of the present application is shown;

[0027] Figure 4 A schematic structural diagram of a squirrel cage proposed according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] It is easy to understand that according to the technical solution of the present application, without changing the essential spirit of the present application, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the entirety of the present application or as a limitation or restriction on the technical solution of the present application.

[0029] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directional terms should not be interpreted as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for description and distinction purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components or the order or assembly order of the components.

[0030] The first aspect of the present application provides a rotor core 100. Figure 1, which shows a schematic structural diagram of a rotor core 100 proposed according to an embodiment of the present application. The rotor core 100 is used for an asynchronous induction motor, and includes four annular sub-cores 101, 102, 103, 104 arranged adjacent to each other along the axial direction of the rotor 10, and grooves 111 are uniformly constructed on the outer periphery of the sub-cores 101, 102, 103, 104 along the peripheral direction. The sub-cores 101, 102, 103, 104 are especially formed by stacking a plurality of core punching sheets at a certain angle. The grooves 111 of the sub-cores 101, 102, 103, 104 are constructed as linear grooves 111, which extend at a twisted angle relative to the axial direction. That is to say, the grooves 111 of the sub-cores 101, 102, 103, 104 are not arranged parallel to the axial direction like a normal rotor core, but are arranged obliquely to the axial direction. "The groove extends at a twisted angle relative to the axial direction" can also be described as that the end point of the groove 111 is offset by the angle relative to the starting point of the groove 111 in the circumferential direction of the sub-cores 101, 102, 103, 104. In one embodiment of the present application, the angle is preferably the spacing angle between two adjacent grooves 111 in the circumferential direction. That is to say, when the end point and the starting point of the groove 111 are projected together onto a plane perpendicular to the axial direction, the end point of the groove 111 is offset by the angle between the two adjacent grooves 111 in the circumferential direction in a clockwise or counterclockwise direction compared to the starting point of the groove 111. Setting the angle as the spacing angle between two adjacent grooves 111 in the circumferential direction can ensure that the number of grooves in the sub-cores 101, 102, 103, 104 is the same as that of the usual sub-core (i.e., the sub-core whose groove extension direction is parallel to the axial direction), which is also beneficial to the manufacture of the sub-core.

[0031] exist Figure 1 In the embodiment of the present invention, the grooves of all the sub-cores 101, 102, 103, and 104 are connected end to end in sequence to form the rotor slot 110. Figure 1 The rotor core 100 is sequentially called the first sub-core 101, the second sub-core 102, the third sub-core 103 and the fourth sub-core 104 in the axial direction. The four sub-cores 101, 102, 103, 104 are constructed identically, and their grooves 111 are connected end to end to form a rotor slot 110 that is V-shaped in the axial direction. The grooves 111 of the first sub-core 101 and the grooves 111 of the second sub-core 102 form one side of the V-shape, the grooves 111 of the third sub-core 103 and the grooves 111 of the fourth sub-core 104 form the other side of the V-shape, and the two sides of the V-shape are symmetrical to each other in the axial direction. Through this V-shaped construction of the rotor slot 110 and the symmetrical structure in the axial direction, the tooth harmonic magnetic field can be weakened, the amplitude of the electromagnetic radial force can be reduced, and the torsional vibration caused by the axial spatial phase asymmetry can be eliminated.

[0032] In an embodiment not shown, in the case of a rotor core having four sub-cores 101, 102, 103, 104, the rotor slot 110 may also have a shape in which two V-shapes are connected side by side in the axial direction. In this embodiment, the grooves 111 of the first sub-core 101 and the second sub-core 102 form a V-shape, and the grooves 111 of the third sub-core 103 and the fourth sub-core 104 form another V-shape, and the two V-shapes are symmetrical to each other in the axial direction.

[0033] refer to Figure 2 , which shows a schematic diagram of the structure when the rotor core 200 proposed in another embodiment of the present application is installed on the rotor. In this embodiment, the rotor core 200 includes six sub-cores, which are defined as the first sub-core 201, the second sub-core 202, the third sub-core 203, the fourth sub-core 204, the fifth sub-core 205 and the sixth sub-core 206 arranged in sequence along the axial direction. Among them, the six sub-cores 201, 202, 203, 204, 205, 206 have the same structure, and the rotor slot 210 has a shape of three V-shaped connected side by side in the axial direction. The grooves 211 of the first sub-core 201 and the second sub-core 202 form a V shape, the third sub-core 203 and the fourth sub-core 204 form a V shape, and the fifth sub-core 205 and the sixth sub-core 206 form a V shape, and the three V shapes are symmetrical about the center of the V shape in the middle in the axial direction.

[0034] In an embodiment not shown, in the case of a rotor core 200 having six sub-cores 201, 202, 203, 204, 205, 206, the rotor slot 210 may also have a V-shaped shape in the axial direction. In this embodiment, the grooves 211 of the first sub-core 201, the second sub-core 202, and the third sub-core 203 form one side of the V-shape, and the grooves 211 of the fourth sub-core 204, the fifth sub-core 205, and the sixth sub-core 206 form the other side of the V-shape, and the two sides of the V-shape are symmetrical to each other in the axial direction.

[0035] It should be understood that the rotor core is not limited to having 4 sub-cores or 6 sub-cores, but may also have any other even number of sub-cores, and the sub-cores may also adopt different structural forms, as long as the rotor slots have a V-shaped shape or a plurality of V-shaped shapes connected side by side in the axial direction. The above-mentioned rotor core structural method can well change the vibration and noise performance of the asynchronous motor, thereby improving its overall NVH performance.

[0036] In one embodiment of the present application, the V-shaped angle formed by the grooves 111 and 211 satisfies the following formula:

[0037]

[0038] Wherein, β is the V-shaped angle, L is the axial length of the rotor, R is the radius of the rotor, α is the circumferential spacing angle between two adjacent stator slots or two adjacent rotor slots, and k is a correction coefficient, k is, for example, greater than 0.8 and less than 1.1.

[0039] The second aspect of the present application provides an asynchronous motor rotor 10. Figure 3 , which shows a schematic structural diagram of an asynchronous motor rotor 10 according to an embodiment of the present application. The asynchronous motor rotor 10 includes a rotor core (especially the rotor cores 100 and 200 described above) and a cage 300. The cage 300 includes a guide bar 301 and an end ring 302 connected to both ends of the guide bar 301. The guide bar 301 is arranged in the rotor slot 111 in a shape matching with the rotor slot 111, so that Figure 3 In the embodiment, the guide bar 301 is arranged to be V-shaped when viewed in the axial direction (matching the rotor core 100, i.e. Figure 1 The end rings 302 are arranged at both ends of the rotor core 100. In one embodiment of the present application, the guide bar 301 and the end ring 302 are integrally formed, especially integrally formed by a centrifugal casting process.

[0040] In one embodiment of the present application, the porosity between adjacent conductive bars 301 is less than or equal to 2%, so that the consistency of the conductive bar casting quality can be maintained as much as possible, thereby improving the NVH consistency of the asynchronous motor.

[0041] The third aspect of the present application proposes an asynchronous motor, which includes the above-mentioned asynchronous motor rotor 10. The motor rotor speed of the asynchronous motor is lower than the speed of the stator rotating magnetic field. When the motor is working, three-phase alternating current is passed through the stator winding to form a rotating alternating magnetic field. At the same time, the rotor speed is lower than the stator magnetic field speed, so that the rotor bars will cut the stator rotating magnetic field to induce current in the closed bar loop. The stator rotating magnetic field and the magnetic field induced by the rotor interact with each other, output torque on the rotor, and drive the rotor to rotate.

[0042] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present application should be within the legal protection scope of the present application.

Claims

1. A rotor core, characterized in that: The rotor core includes at least two annular sub-cores arranged adjacent to each other in the axial direction of the rotor, and grooves are uniformly constructed along the circumferential direction on the outer periphery of the sub-cores. The grooves extend at an angle twisted relative to the axial direction. The grooves of all the sub-cores form rotor slots, and the rotor slots have a V-shape in the axial direction or a plurality of V-shapes connected side by side.

2. The rotor core according to claim 1, characterized in that: The V-shaped angle satisfies the following formula: Among them, β is the V-shaped angle, L is the axial length of the rotor, R is the radius of the rotor, α is the circumferential spacing angle between two adjacent stator slots or two adjacent rotor slots, and k is the correction coefficient.

3. The rotor core according to claim 1, characterized in that: The rotor core includes a first sub-core, a second sub-core, a third sub-core and a fourth sub-core which are arranged adjacent to each other in sequence along the axial direction. The four sub-cores have the same structure. The rotor slots have a V-shape in the axial direction. The grooves of the first sub-core and the second sub-core form one side of the V-shape, the third sub-core and the fourth sub-core form the other side of the V-shape, and the two sides of the V-shape are symmetrical to each other in the axial direction.

4. The rotor core according to claim 1, characterized in that: The rotor core includes a first sub-core, a second sub-core, a third sub-core and a fourth sub-core which are arranged adjacent to each other in sequence along the axial direction. The four sub-cores have the same structure. The rotor slots have two V-shaped shapes connected side by side in the axial direction. The grooves of the first sub-core and the second sub-core form a V-shape, and the third sub-core and the fourth sub-core form a V-shape. The two V-shapes are symmetrical to each other in the axial direction.

5. The rotor core according to claim 1, characterized in that: The rotor core includes a first sub-core, a second sub-core, a third sub-core, a fourth sub-core, a fifth sub-core and a sixth sub-core which are arranged adjacent to each other in sequence along the axial direction. The six sub-cores have the same structure. The rotor slots have three V-shaped shapes connected side by side in the axial direction. The grooves of the first sub-core and the second sub-core form a V-shape, the third sub-core and the fourth sub-core form a V-shape, and the fifth sub-core and the sixth sub-core form a V-shape. The three V-shapes are symmetrical about the center of the V-shape in the middle in the axial direction.

6. The rotor core according to claim 1, characterized in that: The torsion angle of the groove relative to the axial direction is equal to the interval angle between two adjacent grooves in the circumferential direction.

7. An asynchronous motor rotor, characterized in that: It comprises a rotor core and a squirrel cage according to any one of claims 1 to 6, the squirrel cage comprises a conductor bar and end rings connected at both ends of the conductor bar, the conductor bar is arranged in the rotor slot in a shape matching the rotor slot, and the end rings are arranged at both ends of the rotor core.

8. The asynchronous motor rotor according to claim 7, characterized in that: The squirrel cage is integrally formed by a centrifugal casting process.

9. The asynchronous motor rotor according to claim 8, characterized in that: The porosity between adjacent conductive bars is less than or equal to 2%.

10. An asynchronous motor, characterized in that: The asynchronous motor comprises an asynchronous motor rotor according to any one of claims 1 to 9.

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